@article{LorenzanaSeibold, author = {Lorenzana, Jos{\´e} and Seibold, G{\"o}tz}, title = {Unified description of charge and spin excitations of stripes in cuprates}, language = {en} } @article{DiCioloLorenzanaSeiboldetal., author = {Di Ciolo, A. and Lorenzana, Jos{\´e} and Seibold, G{\"o}tz and Grilli, Marco}, title = {Paramagnetic stripes in cuprates: charge inhomogeneity coexisting with large Fermi surfaces}, language = {en} } @article{GuentherSeibold, author = {G{\"u}nther, Falk and Seibold, G{\"o}tz}, title = {Time-dependent Gutzwiller theory of pair fluctuations in the Hubbard model}, language = {en} } @article{SeiboldLorenzana, author = {Seibold, G{\"o}tz and Lorenzana, Jos{\´e}}, title = {Doping dependence of spin excitations in the stripe phase of high-Tc superconductors}, language = {en} } @article{LorenzanaSeibold, author = {Lorenzana, Jos{\´e} and Seibold, G{\"o}tz}, title = {Dynamic properties of inhomogeneous states in cuprates}, language = {en} } @article{EreminVarlamovEremeninetal., author = {Eremin, M. and Varlamov, Sergej and Eremenin, I. and Seibold, G{\"o}tz}, title = {Influence of incommensurability on SDW and CDW amplitudes in underdoped cuprates}, language = {en} } @misc{SeiboldBeccaBuccietal., author = {Seibold, G{\"o}tz and Becca, Federico and Bucci, F. and Castellani, Claudio and Di Castro, Carlo and Grilli, Marco}, title = {Spectral properties of incommensurate charge-density wave systems}, language = {en} } @article{SeiboldSigmundHizhnyakov, author = {Seibold, G{\"o}tz and Sigmund, Ernst and Hizhnyakov, Vladimir}, title = {Spin-Polaron Formation and Phase Separation}, language = {en} } @article{SeiboldSeidelSigmund, author = {Seibold, G{\"o}tz and Seidel, J. and Sigmund, Ernst}, title = {Inhomogeneous Spin Structures in High-Tc Cuprates}, language = {en} } @article{SeiboldSigmund, author = {Seibold, G{\"o}tz and Sigmund, Ernst}, title = {Gutzwiller and Slave-Boson Methods for Intersite Coulomb Interactions}, language = {en} } @article{BillHizhnyakovNevedrovetal., author = {Bill, Andreas and Hizhnyakov, Vladimir and Nevedrov, D. and Seibold, G{\"o}tz and Sigmund, Ernst}, title = {Electronic inhomogeneities, electron-lattice and pairinginteractions in high-Tc superconductors}, language = {en} } @misc{SeiboldCastellaniDiCastroetal., author = {Seibold, G{\"o}tz and Castellani, Claudio and Di Castro, Carlo and Grilli, Marco}, title = {Striped phases in the two-dimensional Hubbard model with long-rangeCoulomb interaction}, language = {en} } @article{SeiboldSigmundHizhnyakov, author = {Seibold, G{\"o}tz and Sigmund, Ernst and Hizhnyakov, Vladimir}, title = {Unrestricted slave-boson mean-field approximation for the two-dimensional Hubbard model}, series = {Physical review}, volume = {57}, journal = {Physical review}, number = {12}, issn = {0556-2805}, pages = {6937 -- 6942}, language = {en} } @article{FeinbergGermainGrillietal., author = {Feinberg, D. and Germain, P. and Grilli, Marco and Seibold, G{\"o}tz}, title = {Joint superexchange - Jahn-Teller mechanism for A-typeantiferromagnetism in LaMnO3}, language = {en} } @misc{Seibold, author = {Seibold, G{\"o}tz}, title = {Vortex, skyrmion and elliptical domain wall textures in thetwo-dimensional Hubbard model}, series = {Physical review B}, volume = {58}, journal = {Physical review B}, number = {23}, issn = {1550-235X}, pages = {15520 -- 15527}, language = {en} } @article{SeiboldVarlamov, author = {Seibold, G{\"o}tz and Varlamov, Sergej}, title = {Relationship between incommensurability and superconductivity in Peierls distorted charge-density-wave systems}, series = {Physical review : B}, volume = {60}, journal = {Physical review : B}, issn = {0556-2805}, pages = {13056}, language = {en} } @misc{SeiboldCastellaniDiCastroetal., author = {Seibold, G{\"o}tz and Castellani, Claudio and Di Castro, Carlo and Grilli, Marco}, title = {Fermi surface and photoemission lineshape of incommensurate CDW systems}, language = {en} } @article{RuckhSeiboldSigmund, author = {Ruckh, R. and Seibold, G{\"o}tz and Sigmund, Ernst}, title = {Influence of quantum fluctuations on solitary-wave acoustic polaron motion}, language = {en} } @article{SeiboldSigmundHizhnyakov, author = {Seibold, G{\"o}tz and Sigmund, Ernst and Hizhnyakov, Vladimir}, title = {Spin-cluster states in CuO2 planes}, series = {Physical review B}, volume = {48}, journal = {Physical review B}, number = {10}, issn = {0556-2805}, pages = {7537 -- 7544}, language = {en} } @article{SeiboldSigmund, author = {Seibold, G{\"o}tz and Sigmund, Ernst}, title = {Metal-insulator transition in doped bismuthate superconductors}, language = {en} } @article{SigmundHizhnyakovSeibold, author = {Sigmund, Ernst and Hizhnyakov, Vladimir and Seibold, G{\"o}tz}, title = {Phase-Separation in High-Tc Superconductors}, series = {Physica C : Superconductivity}, volume = {Vol. 235-240}, journal = {Physica C : Superconductivity}, number = {1}, issn = {0921-4534}, pages = {253 -- 256}, language = {en} } @article{LetzSeiboldSigmund, author = {Letz, M. and Seibold, G{\"o}tz and Sigmund, Ernst}, title = {Percolative Phase-Separation-Mean Field Calculations of Spin-Polarized States in CuO2 Planes}, language = {en} } @article{SeiboldLetzSigmundetal., author = {Seibold, G{\"o}tz and Letz, M. and Sigmund, Ernst and Hizhnyakov, Vladimir}, title = {Mean-Field Theories of Spin-Cluster States in copper oxide planes}, language = {en} } @article{SigmundHizhnyakovSeibold, author = {Sigmund, Ernst and Hizhnyakov, Vladimir and Seibold, G{\"o}tz}, title = {Electronic Phase Separation in High-Tc Superconductors}, language = {en} } @article{SigmundSeiboldBilletal., author = {Sigmund, Ernst and Seibold, G{\"o}tz and Bill, Andreas and Wulf, Ulrich and Isenmann, G. and Essl, W.}, title = {Dynamische Eigenschaften von Festk{\"o}rpern und Molekularen Strukturen}, language = {en} } @phdthesis{Seibold, author = {Seibold, G{\"o}tz}, title = {Spin-polarisierte Quasiteilchen in der Hochtemperatursupraleitung}, publisher = {Aachen : Shaker}, language = {de} } @article{SeiboldSigmund, author = {Seibold, G{\"o}tz and Sigmund, Ernst}, title = {Differences between one and multiband Hubbard models}, language = {en} } @article{SeiboldVarlamov, author = {Seibold, G{\"o}tz and Varlamov, Sergej}, title = {Spectral properties of incommensurate CDW scattering in cuprates}, language = {en} } @article{LorenzanaSeibold, author = {Lorenzana, Jos{\´e} and Seibold, G{\"o}tz}, title = {Metallic mean-field stripes, incommensurability and chemicalpotential in cuprates}, language = {en} } @article{VarlamovSeibold, author = {Varlamov, Sergej and Seibold, G{\"o}tz}, title = {Effective interactions in the stripe state of the two-dimensional Hubbard model}, language = {en} } @article{VarlamovSeibold, author = {Varlamov, Sergej and Seibold, G{\"o}tz}, title = {Influence of the pseudogap on the superconductivity-inducedphonon renormalization in high-Tc superconductors}, language = {en} } @misc{SeiboldVarlamov, author = {Seibold, G{\"o}tz and Varlamov, Sergej}, title = {Effect of incommensurate charge-density wave scattering on theelectronic structure of high-Tc cuprates (I)}, series = {Journal of Superconductivity}, volume = {15}, journal = {Journal of Superconductivity}, number = {5}, issn = {0896-1107}, pages = {387 -- 388}, language = {en} } @misc{SeiboldVarlamov, author = {Seibold, G{\"o}tz and Varlamov, Sergej}, title = {Effect of incommensurate charge-density wave scattering on theelectronic structure of high-Tc cuprates (II)}, series = {Journal of Superconductivity}, volume = {15}, journal = {Journal of Superconductivity}, number = {6}, issn = {0896-1107}, pages = {505 -- 506}, language = {en} } @article{Seibold, author = {Seibold, G{\"o}tz}, title = {Grundlagen und Anwendungen der Supraleitung}, series = {Unterrichtsbl{\"a}tter Deutsche Telekom}, volume = {55}, journal = {Unterrichtsbl{\"a}tter Deutsche Telekom}, issn = {0949-3387}, pages = {S. 240}, language = {de} } @incollection{SeiboldCastellaniDiCastroetal., author = {Seibold, G{\"o}tz and Castellani, Claudio and Di Castro, Carlo and Grilli, Marco}, title = {Domain wall structures in the two-dimensional Hubbard modelwith long-range Coulomb interaction}, series = {Stripes and Related Phenomena}, booktitle = {Stripes and Related Phenomena}, editor = {Bianconi, Antonio and Saini, Naurang L.}, publisher = {Kluwer Academic Plenum}, address = {New York}, isbn = {0-306-46419-5}, doi = {10.1007/0-306-47100-0_18}, pages = {151 -- 157}, language = {en} } @misc{SeiboldCastellaniDiCastroetal., author = {Seibold, G{\"o}tz and Castellani, Claudio and Di Castro, Carlo and Grilli, Marco}, title = {Role of the long-range Coulomb interaction on the formation of striped phases in the two-dimensional Hubbard model}, series = {High temperature superconductivity, Coral Gables, Florida, January 1999}, journal = {High temperature superconductivity, Coral Gables, Florida, January 1999}, editor = {Barnes, Stewart E.}, publisher = {AIP Publishing}, address = {Melville, New York}, isbn = {1-56396-880-0}, doi = {10.1063/1.59651}, language = {en} } @incollection{HizhnyakovSigmundSeibold, author = {Hizhnyakov, Vladimir and Sigmund, Ernst and Seibold, G{\"o}tz}, title = {Polaron Formation and Percolative Phase Separation}, series = {Phase Separation in Cuprate Superconductors}, booktitle = {Phase Separation in Cuprate Superconductors}, publisher = {Springer}, address = {Berlin [u.a.]}, isbn = {3-540-57681-9}, pages = {50 -- 65}, language = {en} } @article{SeiboldGrilli, author = {Seibold, G{\"o}tz and Grilli, Marco}, title = {Theory of isotope dependence of photoemission spectra ofhigh-Tc superconducting cuprates}, language = {en} } @article{SeiboldLorenzana, author = {Seibold, G{\"o}tz and Lorenzana, Jos{\´e}}, title = {Magnetic fluctuations of stripes in the high temperature cuprate superconductors}, language = {en} } @article{SeiboldLorenzana, author = {Seibold, G{\"o}tz and Lorenzana, Jos{\´e}}, title = {Stability of metallic stripes in the extended one-band Hubbard model}, language = {en} } @article{SeiboldBeccaRubinetal., author = {Seibold, G{\"o}tz and Becca, Federico and Rubin, P. and Lorenzana, Jos{\´e}}, title = {Time-dependent Gutzwiller theory of magnetic excitations in the Hubbard model}, language = {en} } @article{LorenzanaSeibold, author = {Lorenzana, Jos{\´e} and Seibold, G{\"o}tz}, title = {Dynamical and statical properties of stripes in cuprates}, language = {en} } @article{VarlamovSeibold, author = {Varlamov, Sergej and Seibold, G{\"o}tz}, title = {Temperature dependence of the collective mode and its influence on theband splitting in bilayer cuprates}, language = {en} } @article{LorenzanaSeibold, author = {Lorenzana, Jos{\´e} and Seibold, G{\"o}tz}, title = {Dynamics of metallic stripes in cuprates}, language = {en} } @article{SeiboldBeccaLorenzana, author = {Seibold, G{\"o}tz and Becca, Federico and Lorenzana, Jos{\´e}}, title = {Inhomogeneous Gutzwiller approximation with random phase fluctuationsfor the Hubbard model}, language = {en} } @misc{SchmeisserSchmidtSeiboldetal., author = {Schmeißer, Dieter and Schmidt, Stephan and Seibold, G{\"o}tz and Cherkashinin, Gennady and Jaegermann, Wolfram}, title = {Localized Gap States in LiCoO2 and their Influence on the Transport Properties in Li-Ion Batteries}, series = {ECS Transactions}, volume = {25}, journal = {ECS Transactions}, number = {35}, issn = {1938-5862}, pages = {37 -- 45}, language = {en} } @misc{OelsenSeiboldBuenemann, author = {Oelsen, E. von and Seibold, G{\"o}tz and B{\"u}nemann, J{\"o}rg}, title = {The time-dependent Gutzwiller theory for multi-band Hubbard models}, series = {New Journal of Physics}, volume = {13}, journal = {New Journal of Physics}, issn = {1367-2630}, pages = {113031-01 -- 113031-42}, language = {en} } @misc{MondalKumarChandetal., author = {Mondal, Mintu and Kumar, Sanjeev and Chand, Madhavi and Kamlapure, Anand and Saraswat, Garima and Seibold, G{\"o}tz and Benfatto, Lara and Raychaudhuri, Pratap}, title = {Role of the Vortex-Core Energy on the Berezinskii-Kosterlitz-Thouless Transition in Thin Films of NbN}, doi = {10.1103/PhysRevLett.107.217003}, language = {en} } @misc{OelsenSeiboldBuenemann, author = {Oelsen, E. von and Seibold, G{\"o}tz and B{\"u}nemann, J{\"o}rg}, title = {Time-Dependent Gutzwiller Theory for Multiband Hubbard Models}, series = {Physical Review Letters}, volume = {107}, journal = {Physical Review Letters}, number = {7}, issn = {1079-7114}, pages = {076402-01 -- 076402-04}, language = {en} } @misc{SeiboldMarkiewiczLorenzana, author = {Seibold, G{\"o}tz and Markiewicz, Richard S. and Lorenzana, Jos{\´e}}, title = {Spin canting as a result of the competition between stripesand spirals in cuprates}, language = {en} } @misc{MarkiewiczLorenzanaSeiboldetal., author = {Markiewicz, Richard S. and Lorenzana, Jos{\´e} and Seibold, G{\"o}tz and Bansil, Arun}, title = {Competing phases on the cuprates: Charge vs spin order}, language = {en} } @misc{SeiboldGrilliLorenzana, author = {Seibold, G{\"o}tz and Grilli, Marco and Lorenzana, Jos{\´e}}, title = {Influence of correlations on transitive electron-phonon couplings in cuprate superconductors}, language = {en} } @misc{SeiboldGrilliLorenzana, author = {Seibold, G{\"o}tz and Grilli, Marco and Lorenzana, A.}, title = {Dynamics of Electronic Inhomogeneities in Cuprates}, language = {en} } @article{SeiboldGrilli, author = {Seibold, G{\"o}tz and Grilli, Marco}, title = {Influence of incommensurate dynamic charge-density wave scatteringon the line shape of superconducting high-Tc cuprates}, series = {Physical Review B}, volume = {63}, journal = {Physical Review B}, number = {22}, issn = {1550-235X}, pages = {224505}, language = {en} } @inproceedings{SigmundHizhnyakovSeibold, author = {Sigmund, Ernst and Hizhnyakov, Vladimir and Seibold, G{\"o}tz}, title = {Percolative Phase Separation and High-Tc superconductivity}, series = {Proceedings of the Workshop on Phase Separation in Cuprate Semiconductors, Erice, Italy, 1992}, booktitle = {Proceedings of the Workshop on Phase Separation in Cuprate Semiconductors, Erice, Italy, 1992}, publisher = {World Scientific}, address = {Singapore [u.a.]}, isbn = {981-02-1274-7}, pages = {46 -- 66}, language = {en} } @misc{BazartBoneinHokampetal., author = {Bazart, C{\´e}cile and Bonein, Aur{\´e}lie and Hokamp, Sascha and Seibold, G{\"o}tz}, title = {Bahavioural Economics and Tax Evasion: Calibrating an Agent-based Econophysics Model with Experimental Tax Compliance Data}, series = {Journal of Tax Administration}, volume = {2}, journal = {Journal of Tax Administration}, number = {1}, pages = {126 -- 144}, language = {en} } @misc{MarkiewiczLorenzanaSeiboldetal., author = {Markiewicz, Richard S. and Lorenzana, Jos{\´e} and Seibold, G{\"o}tz and Bansil, Arun}, title = {Short range smectic order driving long range nematic order: example of cuprates}, series = {Scientific reports}, volume = {6}, journal = {Scientific reports}, issn = {2045-2322}, doi = {10.1038/srep19678}, pages = {19678}, language = {en} } @misc{SeiboldBenfattoCastellanietal., author = {Seibold, G{\"o}tz and Benfatto, Lara and Castellani, Claudio and Lorenzana, Jos{\´e}}, title = {Current Correlations in Strongly Disordered Superconductors}, series = {Journal of Superconductivity and Novel Magnetism}, volume = {29}, journal = {Journal of Superconductivity and Novel Magnetism}, number = {3}, doi = {10.1007/s10948-015-3300-6}, pages = {577 -- 580}, language = {en} } @misc{TeaCastellaniSeiboldetal., author = {Tea, C. and Castellani, Claudio and Seibold, G{\"o}tz and Benfatto, Lara}, title = {Nonrelativistic Dynamics of the Amplitude (Higgs) Mode in Superconductors}, series = {Physical Review Letters}, volume = {115}, journal = {Physical Review Letters}, issn = {1079-7114}, doi = {http://dx.doi.org/10.1103/PhysRevLett.115.157002}, pages = {157002}, language = {en} } @misc{SeiboldCapraraGrillietal., author = {Seibold, G{\"o}tz and Caprara, Sergio and Grilli, Marco and Raimondi, Roberto}, title = {Intrinsic spin Hall effect in systems with striped spin-orbit coupling}, series = {epl : a letters journal exploring the frontiers of physics}, volume = {112}, journal = {epl : a letters journal exploring the frontiers of physics}, number = {1}, issn = {1286-4854}, doi = {http://dx.doi.org/10.1209/0295-5075/112/17004}, pages = {17004-p1 -- 17004-p6}, language = {en} } @misc{CeaBucheliSeiboldetal., author = {Cea, Tommaso and Bucheli, Daniel and Seibold, G{\"o}tz and Benfatto, Lara and Lorenzana, Jos{\´e} and Castellani, Claudio}, title = {Optical excitation of phase modes in strongly disordered superconductors}, series = {Physical Review B}, volume = {89}, journal = {Physical Review B}, issn = {2469-9969}, doi = {10.1103/PhysRevB.89.174506}, pages = {174506}, abstract = {According to the Goldstone theorem the breaking of a continuous U(1) symmetry comes along with the existence of low-energy collective modes. In the context of superconductivity these excitations are related to the phase of the superconducting (SC) order parameter and for clean systems are optically inactive; that is, single-mode excitations do not directly couple to light. Here we show that for strongly disordered superconductors phase modes acquire a dipole moment and appear as a subgap spectral feature in the optical conductivity. This finding is obtained with both a gauge-invariant random-phase approximation scheme based on a fermionic Bogoliubov-de Gennes state and a prototypical bosonic model for disordered superconductors. In the strongly disordered regime, where the system displays an effective granularity of the SC properties, the optically active dipoles are linked to the isolated SC islands, offering a new perspective for realizing microwave optical devices.}, language = {en} } @misc{BucheliGrilliPeronacietal., author = {Bucheli, Daniel and Grilli, Marco and Peronaci, F. and Seibold, G{\"o}tz and Caprara, Sergio}, title = {Phase diagrams of voltage-gated oxide interfaces with strong Rashba coupling}, series = {Physical Review B}, volume = {89}, journal = {Physical Review B}, issn = {2469-9969}, doi = {10.1103/PhysRevB.89.195448}, abstract = {We propose a model for the two-dimensional electron gas formed at the interface of oxide heterostructures that includes a Rashba spin-orbit coupling proportional to an electric field oriented perpendicularly to the interface. Taking into account the electron density dependence of this electric field confining the electron gas at the interface, we report the occurrence of a phase separation instability (signaled by a negative compressibility) for realistic values of the spin-orbit coupling and of the electronic band-structure parameters at zero temperature. We extend the analysis to finite temperatures and in the presence of an in-plane magnetic field, thereby obtaining two phase diagrams that exhibit a phase separation dome. By varying the gating potential, the phase separation dome may shrink and vanish at zero temperature into a quantum critical point where the charge fluctuates dynamically. Similarly, the phase separation may be spoiled by a planar magnetic field even at zero temperature leading to a line of quantum critical points.}, language = {en} } @misc{SeiboldDiCastroGrillietal., author = {Seibold, G{\"o}tz and Di Castro, Carlo and Grilli, Marco and Lorenzana, Jos{\´e}}, title = {Spin excitations of ferronematic order in underdoped cuprate superconductors}, series = {Scientific reports}, journal = {Scientific reports}, number = {4}, issn = {2045-2322}, doi = {10.1038/srep05319}, pages = {5319}, abstract = {High-temperature superconductors exhibit a characteristic hourglass-shaped spectrum of magnetic fluctuations which most likely contribute to the pairing glue in the cuprates. Recent neutron scattering experiments in strongly underdoped compounds have revealed a significant low energy anisotropy of these fluctuations which we explain by a model in which topological defects of the antiferromagnet clump to producing domain wall segments with ferronematic order. This state does not invoke global charge order but breaks C4 rotational and inversion symmetry. The incommensurability of the low doping charge-disordered state is in good agreement with experiment and interpolates smoothly with the incommensurability of the stripe phase at higher doping. Within linear spin-wave theory the dynamic structure factor is in very good agreement with inelastic neutron scattering data and can account for the observed energy dependent anisotropy.}, language = {en} } @misc{SeiboldMarkiewiczLorenzana, author = {Seibold, G{\"o}tz and Markiewicz, Richard S. and Lorenzana, Jos{\´e}}, title = {Magnetic Structure of Electronic Inhomogeneities in Cuprates: Competition between Stripes and Spirals}, series = {Acta Physica Polonica A}, volume = {121}, journal = {Acta Physica Polonica A}, number = {5-6}, issn = {1898-794X}, pages = {1019 -- 1021}, abstract = {It is shown that the magnetic structure of high-T c superconductors is strongly influenced by the next-nearest neighbor hopping parameter t' which distinguishes different families of cuprates. Our investigations indicate that uniform spirals get favored by a large t'=t ratio but are unstable at small doping towards stripes with spin canting. For large /t'/t/ spirals can be stabilized under certain conditions in the overdoped regime which may explain the elastic incommensurate magnetic response recently observed in iron-co-doped Bi2201 materials.}, language = {en} } @misc{SeiboldMarkiewiczLorenzana, author = {Seibold, G{\"o}tz and Markiewicz, Richard S. and Lorenzana, Jos{\´e}}, title = {Stripes with Spin Canting in the Three-Band Hubbard Model}, series = {Journal of Superconductivity and Novel Magnetism}, volume = {26}, journal = {Journal of Superconductivity and Novel Magnetism}, number = {1}, issn = {1557-1939}, doi = {10.1007/s10948-012-1701-3}, pages = {49 -- 52}, abstract = {In underdoped cuprates, both stripes and spiral states may account for the incommensurate spin response observed by elastic neutron scattering experiments. Here, we investigate the respective stability of both textures within the framework of the three-band Hubbard model which we treat within the unrestricted Gutzwiller approximation. Our calculations indicate that for parameter sets appropriate for lanthanum cuprates and small doping nor purely longitudinal stripes nor uniform spirals are stable but stripes with significant spin canting. Indeed at small doping uniform spirals are unstable toward nanoscale phase separation.}, language = {en} } @misc{LemarieKamlapureBenfattoetal., author = {Lemari{\´e}, Gabriel and Kamlapure, Anand and Benfatto, Lara and Lorenzana, Jos{\´e} and Seibold, G{\"o}tz and Ganguli, S. C. and Raychaudhuri, Pratap and Castellani, Claudio}, title = {Universal scaling of the order-parameter distribution in strongly disordered superconductors}, series = {Physical Review B}, volume = {87}, journal = {Physical Review B}, number = {18}, issn = {2469-9977}, doi = {10.1103/PhysRevB.87.184509}, pages = {184509}, abstract = {We investigate theoretically and experimentally the statistical properties of the inhomogeneous order-parameter distribution (OPD) at the verge of the superconductor-insulator transition (SIT). We find within two prototype fermionic and bosonic models for disordered superconductors that one can identify a universal rescaling of the OPD. By performing scanning-tunneling microscopy experiments in three samples of NbN with increasing disorder we show that such a rescaling also describes the experimental data with excellent accuracy. These results can provide a breakthrough in our understanding of the SIT.}, language = {en} } @misc{SeiboldCapatiGrillietal., author = {Seibold, G{\"o}tz and Capati, Matteo and Grilli, Marco and Di Castro, Carlo and Grilli, Marco and Lorenzana, Jos{\´e}}, title = {Hidden ferronematic order in underdoped cuprates}, series = {Physical Review B}, volume = {87}, journal = {Physical Review B}, number = {3}, issn = {2469-9969}, doi = {10.1103/PhysRevB.87.035138}, pages = {035138}, abstract = {We study a model for low-doped cuprates where holes aggregate into oriented stripe segments which have a magnetic vortex and antivortex at the extremes. We argue that due to the interaction between segments a ferronematic state with macroscopic polarization is stabilized. This state can be characterized as a charge nematic which, due to the net polarization, breaks inversion symmetry and also exhibits an incommensurate spin modulation. Our calculation can reproduce the doping-dependent spin structure factor of lanthanum cuprates in excellent agreement with experiment and allows to rationalize experiments in which the incommensurability has an order-parameter-like temperature dependence.}, language = {en} } @misc{SeiboldPickhardt, author = {Seibold, G{\"o}tz and Pickhardt, Michael}, title = {Lapse of time effects on tax evasion in an agent-based econophysics model}, series = {Physica A: Statistical Mechanics and its Applications}, volume = {392}, journal = {Physica A: Statistical Mechanics and its Applications}, number = {9}, issn = {0378-4371}, doi = {10.1016/j.physa.2013.01.016}, pages = {2079 -- 2087}, abstract = {We investigate an inhomogeneous Ising model in the context of tax evasion dynamics where different types of agents are parameterized via local temperatures and magnetic fields. In particular, we analyze the impact of lapse of time effects (i.e. backauditing) and endogenously determined penalty rates on tax compliance. Both features contribute to a microfoundation of agent-based econophysics models of tax evasion.}, language = {en} } @misc{PickhardtSeibold, author = {Pickhardt, Michael and Seibold, G{\"o}tz}, title = {Income tax evasion dynamics: Evidence from an agent-based econophysics model}, series = {Journal of Economic Psychology}, volume = {40}, journal = {Journal of Economic Psychology}, issn = {0167-4870}, doi = {10.1016/j.joep.2013.01.011}, pages = {147 -- 160}, abstract = {• We extend existing econophysics models with respect to the behavioral heterogeneity of agents. • We analyze enforcement or audit efficiency. • We compare agent-based tax evasion models in the economics versus the econophysics domain.}, language = {en} } @misc{BuenemannCaponeLorenzanaetal., author = {B{\"u}nemann, J{\"o}rg and Capone, Michael and Lorenzana, Jos{\´e} and Seibold, G{\"o}tz}, title = {Linear-response dynamics from the time-dependent Gutzwiller approximation}, series = {New Journal of Physics}, volume = {15}, journal = {New Journal of Physics}, issn = {1367-2630}, abstract = {Within a Lagrangian formalism, we derive the time-dependent Gutzwiller approximation for general multi-band Hubbard models. Our approach explicitly incorporates the coupling between time-dependent variational parameters and a time-dependent density matrix from which we obtain dynamical correlation functions in the linear-response regime. Our results are illustrated for the one-band model where we show that the interacting system can be mapped to an effective problem of fermionic quasiparticles coupled to 'doublon' (double occupancy) bosonic fluctuations. The latter have an energy on the scale of the on-site Hubbard repulsion U in the dilute limit but become soft at the Brinkman-Rice transition, which is shown to be related to an emerging conservation law of doublon charge and the associated gauge invariance. Coupling with the boson mode produces a structure in the charge response and we find that a similar structure appears in dynamical mean-field theory.}, language = {en} } @misc{SeiboldBenfattoCastellanietal., author = {Seibold, G{\"o}tz and Benfatto, Lara and Castellani, Claudio and Lorenzana, Jos{\´e}}, title = {Superfluid Density and Phase Relaxation in Superconductors with Strong Disorder}, series = {Physical Review Letters}, volume = {108}, journal = {Physical Review Letters}, number = {20}, issn = {1092-0145}, doi = {10.1103/PhysRevLett.108.207004}, pages = {207004}, abstract = {We consider the attractive Hubbard model with on-site disorder as a prototype of a disordered superconductor. We solve the Bogoliubov-de Gennes equations on two-dimensional finite clusters at zero temperature and evaluate the electromagnetic response to a vector potential. We find that the standard decoupling between transverse and longitudinal response does not apply in the presence of disorder. Moreover, the superfluid density is strongly reduced by the relaxation of the phase of the order parameter already at mean-field level when disorder is large. We also find that the anharmonicity of the phase fluctuations is strongly enhanced by disorder. Beyond mean field, this provides an enhancement of quantum fluctuations inducing a zero-temperature transition to a nonsuperconducting phase of disordered preformed pairs. Finally, the connection of our findings with the glassy physics for extreme dirty superconductors is discussed.}, language = {en} } @misc{SeiboldGrilliLorenzana, author = {Seibold, G{\"o}tz and Grilli, Marco and Lorenzana, Jos{\´e}}, title = {Stripes in cuprate superconductors: Excitations and dynamic dichotomy}, series = {Physica C: Superconductivity}, volume = {481}, journal = {Physica C: Superconductivity}, issn = {0921-4534}, doi = {10.1016/j.physc.2012.03.072}, pages = {132 -- 145}, abstract = {We present a short account of the present experimental situation of stripes in cuprates followed by a review of our present understanding of their ground state and excited state properties. Collective modes, the dynamical structure factor, and the optical conductivity of stripes are computed using the time-dependent Gutzwiller approximation applied to realistic one band and three band Hubbard models, and are found to be in excellent agreement with experiment. On the other hand, experiments like angle-resolved photoemission and scanning tunneling microscopy show the coexistence of stripes at high energies with Fermi liquid quasiparticles at low energies. We show that a phenomenological model going beyond mean-field can reconcile this dynamic dichotomy.}, language = {en} } @misc{SeiboldCapraraGrillietal., author = {Seibold, G{\"o}tz and Caprara, Sergio and Grilli, Marco and Raimondi, Roberto}, title = {Non-equilibrium Spin Currents in Systems with Striped Rashba Spin-Orbit Coupling}, series = {Journal of Superconductivity and Novel Magnetism}, volume = {30}, journal = {Journal of Superconductivity and Novel Magnetism}, number = {1}, issn = {1557-1939}, doi = {10.1007/s10948-016-3774-x}, pages = {123 -- 128}, abstract = {It is shown that non-homogeneity in the spin-orbit coupling (SOC) arising from structure inversion asymmetry gives rise to a finite intrinsic spin Hall conductivity in contrast with the corresponding case of a homogeneous SOC in the disordered two-dimensional electron gas. In particular, we examine the inhomogeneity arising from a striped modulation of the Rashba type spin-orbit coupling. A corresponding structure could be realized at oxide interfaces with periodic top gating or in semiconductor heterostructures.}, language = {en} } @misc{CapraraGrilliDiCastroetal., author = {Caprara, Sergio and Grilli, Marco and Di Castro, Carlo and Seibold, G{\"o}tz}, title = {Pseudogap and (An)isotropic Scattering in the Fluctuating Charge-Density Wave Phase of Cuprates}, series = {Journal of Superconductivity and Novel Magnetism}, volume = {30}, journal = {Journal of Superconductivity and Novel Magnetism}, number = {1}, issn = {1557-1939}, doi = {10.1007/s10948-016-3775-9}, pages = {25 -- 30}, abstract = {We present a general scenario for high-temperature superconducting cuprates, based on the presence of dynamical charge density waves (CDWs) and to the occurrence of a CDW quantum critical point, which occurs, e.g., at doping p ≈ 0.16 in YBa2Cu3O6 + δ (YBCO). In this framework, the pseudogap temperature T∗ is interpreted in terms of a reduction of the density of states due to incipient CDW and, at lower temperature to the possible formation of incoherent superconducting pairs. The dynamically fluctuating character of CDW accounts for the different temperatures at which the CDW onset revealed by X-ray scattering (Tons(p)), and the static three-dimensional CDW ordering appear. We also investigate the anisotropic character of the CDW-mediated scattering. We find that this is strongly anisotropic only close to the CDW quantum critical point (QCP) at low temperature and very low energy. It rapidly becomes nearly isotropic and marginal-Fermi-liquid-like away from the CDW QCP and at finite (even rather small) energies. This may reconcile the interpretation of Hall measurements in terms of anisotropic CDW scattering with recent photoemission experiments Bok, J.M., et al. Sci. Adv. 2, e1501329 (2016).}, language = {en} } @misc{SeiboldBenfattoCastellanietal., author = {Seibold, G{\"o}tz and Benfatto, Lara and Castellani, Claudio and Lorenzana, Jos{\´e}}, title = {Amplitude, density, and current correlations of strongly disordered superconductors}, series = {Physical Review B}, volume = {92}, journal = {Physical Review B}, number = {6}, issn = {2469-9969}, doi = {10.1103/PhysRevB.92.064512}, pages = {064512}, abstract = {We investigate the disorder dependence of the static density, amplitude, and current correlations within the attractive Hubbard model supplemented with onsite disorder. It is found that strong disorder favors a decoupling of density and amplitude correlations due to the formation of superconducting (SC) islands. This emergent granularity also induces an enhancement of the density correlations on the SC islands whereas amplitude fluctuations are most pronounced in the "insulating" regions. While density and amplitude correlations are short ranged at strong disorder, we show that current correlations have a long-range tail due to the formation of percolative current paths in agreement with the constant behavior expected from the analysis of one-dimensional models.}, language = {en} } @misc{BovenziFinocchiaroScopignoetal., author = {Bovenzi, Nicolo and Finocchiaro, Francesca and Scopigno, Nicantro and Bucheli, Daniel and Caprara, Sergio and Seibold, G{\"o}tz and Grilli, Marco}, title = {Possible Mechanisms of Electronic Phase Separation in Oxide Interfaces}, series = {Journal of Superconductivity and Novel Magnetism}, volume = {28}, journal = {Journal of Superconductivity and Novel Magnetism}, number = {4}, issn = {1557-1939}, doi = {10.1007/s10948-014-2903-7}, pages = {1273 -- 1277}, abstract = {LaAlO 3/SrTiO 3 and LaTiO 3/SrTiO 3 (LXO / STO) interfaces are known to host a strongly inhomogeneous (nearly) two-dimensional electron gas (2DEG). In this work, we present three unconventional electronic mechanisms of electronic phase separation (EPS) in a 2DEG as a possible source of inhomogeneity in oxide interfaces. Common to all three mechanisms is the dependence of some (interaction) potential on the 2DEGs density. We first consider a mechanism resulting from a sizable density-dependent Rashba spin-orbit coupling. Next, we point out that an EPS may also occur in the case of a density-dependent superconducting pairing interaction. Finally, we show that the confinement of the 2DEG to the interface by a density-dependent, self-consistent electrostatic potential can by itself cause an EPS.}, language = {en} } @misc{SeiboldBucheliCapraraetal., author = {Seibold, G{\"o}tz and Bucheli, Daniel and Caprara, Sergio and Grilli, Marco}, title = {Phase separation and long-wavelength charge instabilities in spin-orbit coupled systems}, series = {EPL Europhysics Letters}, volume = {109}, journal = {EPL Europhysics Letters}, number = {1}, issn = {1286-4854}, doi = {10.1209/0295-5075/109/17006}, pages = {17006}, abstract = {We investigate a two-dimensional electron model with Rashba spin-orbit interaction where the coupling constant \$g=g(n)\$ depends on the electronic density. It is shown that this dependence may drive the system unstable towards a long-wavelength charge density wave (CDW) where the associated second-order instability occurs in close vicinity to global phase separation. For very low electron densities the CDW instability is nesting-induced and the modulation follows the Fermi momentum kF. At higher density the instability criterion becomes independent of kF and the system may become unstable in a broad momentum range. Finally, upon filling the upper spin-orbit split band, finite momentum instabilities disappear in favor of phase separation alone. We discuss our results with regard to the inhomogeneous phases observed at the LaAlO3/SrTiO3 or LaTiO3/SrTiO3 interfaces.}, language = {en} } @misc{SeiboldCapraraGrillietal., author = {Seibold, G{\"o}tz and Caprara, Sergio and Grilli, Marco and Raimondi, Roberto}, title = {Inhomogeneous Rashba spin-orbit coupling and intrinsic spin-Hall effect}, series = {Journal of Magnetism and Magnetic Materials}, volume = {440}, journal = {Journal of Magnetism and Magnetic Materials}, doi = {10.1016/j.jmmm.2016.12.066}, pages = {63 -- 65}, abstract = {The spin-Hall effect is the generation of a transverse spin-current induced by a longitudinal electric field. Among the various scattering mechanisms which can induce a finite spin-Hall effect we focus on the intrinsic contribution arising from a Rashba-type spin-orbit (RSO) coupling which for couplings linear in momentum usually vanishes. Here we show that non-homogeneity in the spin-orbit coupling arising from structure inversion asymmetry gives rise to a finite spin-Hall effect which we exemplify for a system with striped Rashba spin-orbit coupling.}, language = {en} } @misc{CapatiCapraraDiCastroetal., author = {Capati, Matteo and Caprara, Sergio and Di Castro, Carlo and Grilli, Marco and Seibold, G{\"o}tz and Lorenzana, Jos{\´e}}, title = {Electronic polymers and soft-matter-like broken symmetries in underdoped cuprates}, series = {Nature Communications}, volume = {6}, journal = {Nature Communications}, issn = {2041-1723}, doi = {doi:10.1038/ncomms8691}, pages = {7691}, abstract = {Empirical evidence in heavy fermion, pnictide and other systems suggests that unconventional superconductivity appears associated to some form of real-space electronic order. For the cuprates, despite several proposals, the emergence of order in the phase diagram between the commensurate antiferromagnetic state and the superconducting state is not well understood. Here we show that in this regime doped holes assemble in 'electronic polymers'. Within a Monte Carlo study, we find that in clean systems by lowering the temperature the polymer melt condenses first in a smectic state and then in a Wigner crystal both with the addition of inversion symmetry breaking. Disorder blurs the positional order leaving a robust inversion symmetry breaking and a nematic order, accompanied by vector chiral spin order and with the persistence of a thermodynamic transition. Such electronic phases, whose properties are reminiscent of soft-matter physics, produce charge and spin responses in good accord with experiments.}, language = {en} } @incollection{BillHizhnyakovSeibold, author = {Bill, Andreas and Hizhnyakov, Vladimir and Seibold, G{\"o}tz}, title = {Electronic Phase Separation and Electron-Phonon Coupling in Cuprate Superconductors}, series = {High-Tc Copper Oxide Superconductors and Related Novel Materials}, booktitle = {High-Tc Copper Oxide Superconductors and Related Novel Materials}, editor = {Bussmann-Holder, Annette and Keller, Hugo and Bianconi, Antonio}, publisher = {Springer International Publishing}, address = {Cham}, isbn = {978-3-319-52674-4}, doi = {10.1007/978-3-319-52675-1_1}, pages = {1 -- 14}, abstract = {Nanoscale electronic inhomogeneities are nowadays a well established feature of high-temperature superconductors, most prominently exemplified by the observation of charge-ordered states in a large number of cuprate materials. These inhomogeneities have profound consequences for the electron-phonon coupling since they allow for long-range pairing interactions due to the reduced screening supplemented by the enhancement of the electron-phonon vertex due to strong correlations. In this chapter we review the particular contribution of the Stuttgart-Tartu-Cottbus group to this field and discuss how the current status of experimental results provides affirmation to their ideas.}, language = {en} } @misc{MarkiewiczSeiboldLorenzanaetal., author = {Markiewicz, Richard S. and Seibold, G{\"o}tz and Lorenzana, Jos{\´e} and Bansil, Arun}, title = {Gutzwiller charge phase diagram of cuprates, including electron-phonon coupling effects}, series = {New Journal of Physics}, volume = {17}, journal = {New Journal of Physics}, number = {2}, issn = {1367-2630}, doi = {10.1088/1367-2630/17/2/023074}, pages = {023074}, abstract = {Besides significant electronic correlations, high-temperature superconductors also show a strong coupling of electrons to a number of lattice modes. Combined with the experimental detection of electronic inhomogeneities and ordering phenomena in many high-Tc compounds, these features raise the question as to what extent phonons are involved in the associated instabilities. Here we address this problem based on the Hubbard model including a coupling to phonons in order to capture several salient features of the phase diagram of hole-doped cuprates. Charge degrees of freedom, which are suppressed by the large Hubbard U near half-filling, are found to become active at a fairly low doping level. We find that possible charge order is mainly driven by Fermi surface nesting, with competition between a near-\$(\pi ,\pi )\$ order at low doping and antinodal nesting at higher doping, very similar to the momentum structure of magnetic fluctuations. The resulting nesting vectors are generally consistent with photoemission and tunneling observations, evidence for charge density wave order in YBa2Cu3O\$_{7-\delta }\$ including Kohn anomalies, and suggestions of competition between one- and two-q-vector nesting.}, language = {en} } @misc{CapraraDiCastroSeiboldetal., author = {Caprara, Sergio and Di Castro, Carlo and Seibold, G{\"o}tz and Grilli, Marco}, title = {Dynamical charge density waves rule the phase diagram of cuprates}, series = {Physical Review B}, volume = {95}, journal = {Physical Review B}, number = {22}, issn = {2469-9950}, doi = {https://doi.org/10.1103/PhysRevB.95.224511}, pages = {224511}, abstract = {In the last few years, charge density waves (CDWs) have been ubiquitously observed in high-temperature superconducting cuprates and are now the most investigated among the competing orders in the still hot debate on these systems. A wealth of new experimental data raises several fundamental issues that challenge the various theoretical proposals. We here relate our mean-field instability line T0CDW of a strongly correlated Fermi liquid to the pseudogap T∗(p) line, marking in this way the onset of CDW-fluctuations. These fluctuations reduce strongly the mean-field critical line. Controlling this reduction via an infrared frequency cutoff related to the characteristic time of the probes, we account for the complex experimental temperature versus doping phase diagram. We provide a coherent scenario explaining why different CDW onset curves are observed by different experimental probes and seem to extrapolate at zero temperature into seemingly different quantum critical points (QCPs) in the intermediate and overdoped region. The nearly singular anisotropic scattering mediated by these fluctuations also accounts for the rapid changes of the Hall number seen in experiments and provides the first necessary step for a possible Fermi surface reconstruction fully establishing at lower doping. Finally, we show that phase fluctuations of the CDWs, which are enhanced in the presence of strong correlations near the Mott insulating phase, naturally account for the disappearance of the CDWs at low doping with yet another QCP as seen by the experiments.}, language = {en} } @misc{HokampSeibold, author = {Hokamp, Sascha and Seibold, G{\"o}tz}, title = {Tax Compliance and Public Goods Provision An Agent-based Econophysics Approach}, series = {Central European Journal of Economic Modelling and Econometrics}, volume = {6}, journal = {Central European Journal of Economic Modelling and Econometrics}, number = {4}, issn = {2080-0886}, pages = {217 -- 236}, abstract = {We calculate the dynamics of tax evasion within a multi-agent econophysics model which is adopted from the theory of magnetism and previously has been shown to capture the main characteristics from agent-based based models which build on the standard Allingham and Sandmo approach. In particular, we implement a feedback of public goods provision on the decision-making of selfish agents which aim to pursue their self interest. Our results imply that such a feedback enhances the moral attitude of selfish agents thus reducing the percentage of tax evasion. Two parameters govern the behavior of selfish agents, (i) the rate of adaption to changes in public goods provision and (ii) the threshold of perception of public goods provision. Furtheron we analyze the tax evasion dynamics for different agent compositions and under the feedback of public goods provision. We conclude that policymakers may enhance tax compliance behavior via the threshold of perception by means of targeted public relations.}, language = {en} } @incollection{HokampSeibold, author = {Hokamp, Sascha and Seibold, G{\"o}tz}, title = {How Much Rationality Tolerates the Shadow Economy? - An Agent-Based Econophysics Approach}, series = {Advances in social simulation : proceedings of the 9th Conference of the European Social Simulation Association}, booktitle = {Advances in social simulation : proceedings of the 9th Conference of the European Social Simulation Association}, editor = {Kaminski, Bogumil and Koloch, Grzegorz}, publisher = {Springer}, address = {Berlin [u.a.]}, isbn = {978-3-642-39828-5}, doi = {10.1007/978-3-642-39829-2_11}, pages = {128}, abstract = {We calculate the size of the shadow economy within a multi-agent econophysics model previously developed for the study of tax evasion. In particular, we analyze deviating behavior depending on the fraction of rational agents which aim to pursue their self interest. Two audit mechanisms are considered within our model, that are, (i) a constant compliance period which is enforced after black market activities of an agent have been detected and (ii) a backauditing method which determines the compliance period according to the particpation rate in the shadow economy within a previously preassigned time interval. We calibrate our simulation with respect to experimental evidence of tax compliance in France and Germany and give estimates for the percentage of selfish agents in these countries. This implies different policy recommendations that may work to fight the shadow economy, tax evasion, and the like.}, language = {en} } @misc{BovenziCapraraGrillietal., author = {Bovenzi, Nicandro and Caprara, Sergio and Grilli, Marco and Raimondi, Roberto and Scopigno, Niccol{\`o} and Seibold, G{\"o}tz}, title = {Density inhomogeneities and Rashba spin-orbit coupling interplay in oxide interfaces}, series = {Journal of Physics and Chemistry of Solids}, journal = {Journal of Physics and Chemistry of Solids}, issn = {0022-3697}, pages = {12}, abstract = {There is steadily increasing evidence that the two-dimensional electron gas (2DEG) formed at the interface of some insulating oxides like LaAlO3/SrTiO3 and LaTiO3/SrTiO3 is strongly inhomogeneous. The inhomogeneous distribution of electron density is accompanied by an inhomogeneous distribution of the (self-consistent) electric field confining the electrons at the interface. In turn this inhomogeneous transverse electric field induces an inhomogeneous Rashba spin-orbit coupling (RSOC). After an introductory summary on two mechanisms possibly giving rise to an electronic phase separation accounting for the above inhomogeneity, we introduce a phenomenological model to describe the density-dependent RSOC and its consequences. Besides being itself a possible source of inhomogeneity or charge-density waves, the density-dependent RSOC gives rise to interesting physical effects like the occurrence of inhomogeneous spin-current distributions and inhomogeneous quantum-Hall states with chiral "edge" states taking place in the bulk of the 2DEG. The inhomogeneous RSOC can also be exploited for spintronic devices since it can be used to produce a disorder-robust spin Hall effect.}, language = {en} } @misc{SeiboldBenfattoCastellani, author = {Seibold, G{\"o}tz and Benfatto, Lara and Castellani, Claudio}, title = {Application of the Mattis-Bardeen theory in strongly disordered superconductors}, series = {Physical Review B}, volume = {96}, journal = {Physical Review B}, number = {14}, doi = {10.1103/PhysRevB.96.144507}, pages = {144507}, abstract = {The low-energy optical conductivity of conventional superconductors is usually well described by Mattis-Bardeen (MB) theory, which predicts the onset of absorption above an energy corresponding to twice the superconducing (SC) gap parameter Δ. Recent experiments on strongly disordered superconductors have challenged the application of the MB formulas due to the occurrence of additional spectral weight at low energies below 2Δ. Here we identify three crucial items that have to be included in the analysis of optical-conductivity data for these systems: (a) the correct identification of the optical threshold in the Mattis-Bardeen theory and its relation with the gap value extracted from the measured density of states, (b) the gauge-invariant evaluation of the current-current response function needed to account for the optical absorption by SC collective modes, and (c) the inclusion into the MB formula of the energy dependence of the density of states present already above Tc. By computing the optical conductivity in the disordered attractive Hubbard model, we analyze the relevance of all these items, and we provide a compelling scheme for the analysis and interpretation of the optical data in real materials.}, language = {en} } @misc{MiaoLorenzanaSeiboldetal., author = {Miao, Hu and Lorenzana, Jos{\´e} and Seibold, G{\"o}tz and Peng, Yingying and Amorese, Andrea and Yakhou-Harris, Flora and Kummer, Kurt and Brookes, Nicholas B. and Konik, R. M. and Thampy, Vivek and Gu, G. D. and Ghiringhelli, Giacomo Claudio and Braicovich, Lucio and Dean, M. P. M.}, title = {High-temperature charge density wave correlations in La1.875Ba0.125CuO4 without spin-charge locking}, series = {Proceedings of the National Academy of Sciences of the United States of America PNAS}, volume = {114}, journal = {Proceedings of the National Academy of Sciences of the United States of America PNAS}, number = {47}, issn = {1091-6490}, doi = {10.1073/pnas.1708549114}, pages = {12430 -- 12435}, abstract = {Although all superconducting cuprates display charge-ordering tendencies, their low-temperature properties are distinct, impeding efforts to understand the phenomena within a single conceptual framework. While some systems exhibit stripes of charge and spin, with a locked periodicity, others host charge density waves (CDWs) without any obviously related spin order. Here we use resonant inelastic X-ray scattering to follow the evolution of charge correlations in the canonical stripe-ordered cuprate La1.875Ba0.125CuO4 across its ordering transition. We find that high-temperature charge correlations are unlocked from the wavevector of the spin correlations, signaling analogies to CDW phases in various other cuprates. This indicates that stripe order at low temperatures is stabilized by the coupling of otherwise independent charge and spin density waves, with important implications for the relation between charge and spin correlations in the cuprates.}, language = {en} } @misc{SeiboldCapraraGrillietal., author = {Seibold, G{\"o}tz and Caprara, Sergio and Grilli, Marco and Raimondi, Roberto}, title = {Theory of the Spin Galvanic Effect at Oxide Interfaces}, series = {Physical Review Letters}, volume = {119}, journal = {Physical Review Letters}, number = {25}, issn = {1092-0145}, doi = {10.1103/PhysRevLett.119.256801}, abstract = {The spin galvanic effect (SGE) describes the conversion of a nonequilibrium spin polarization into a transverse charge current. Recent experiments have demonstrated a large conversion efficiency for the two-dimensional electron gas formed at the interface between two insulating oxides, LaAlO3 and SrTiO3. Here, we analyze the SGE for oxide interfaces within a three-band model for the Ti t2g orbitals which displays an interesting variety of effective spin-orbit couplings in the individual bands that contribute differently to the spin-charge conversion. Our analytical approach is supplemented by a numerical treatment where we also investigate the influence of disorder and temperature, which turns out to be crucial to providing an appropriate description of the experimental data.}, language = {en} } @misc{BuenemannSeibold, author = {B{\"u}nemann, J{\"o}rg and Seibold, G{\"o}tz}, title = {Charge and pairing dynamics in the attractive Hubbard model: Mode coupling and the validity of linear-response theory}, series = {Physical Review B}, volume = {96}, journal = {Physical Review B}, number = {24}, issn = {2469-9977}, doi = {10.1103/PhysRevB.96.245139}, abstract = {Pump-probe experiments have turned out as a powerful tool in order to study the dynamics of competing orders in a large variety of materials. The corresponding analysis of the data often relies on standard linear-response theory generalized to nonequilibrium situations. Here we examine the validity of such an approach for the charge and pairing response of systems with charge-density wave and (or) superconducting (SC) order. Our investigations are based on the attractive Hubbard model which we study within the time-dependent Hartree-Fock approximation. In particular, we calculate the quench and pump-probe dynamics for SC and charge order parameters in order to analyze the frequency spectra and the coupling of the probe field to the specific excitations. Our calculations reveal that the "linear-response assumption" is justified for small to moderate nonequilibrium situations (i.e., pump pulses) in the case of a purely charge-ordered ground state. However, the pump-probe dynamics on top of a superconducting ground state is determined by phase and amplitude modes which get coupled far from the equilibrium state indicating the failure of the linear-response assumption.}, language = {en} } @incollection{Seibold, author = {Seibold, G{\"o}tz}, title = {From Spins to Agents: An Econophysics Approach to Tax Evasion}, series = {Agent-based Modeling of Tax Evasion: Theoretical Aspects and Computational Simulations}, booktitle = {Agent-based Modeling of Tax Evasion: Theoretical Aspects and Computational Simulations}, editor = {Hokamp, Sascha and Gulyas, Lazlo and Koehler, Matthew and Wijesinghe, Sanith}, publisher = {Wiley}, address = {Weinheim}, isbn = {978-1-119-15570-6}, pages = {315 -- 336}, abstract = {The only single-source guide to understanding, using, adapting, and designing state-of-the-art agent-based modeling of tax evasion A computational method for simulating the behaviour of individuals or groups and their effects on an entire system, agent-based modeling has proven itself to be a powerful new tool for detecting tax fraud. While interdisciplinary groups and individuals working in the tax domain have published numerous articles in diverse peer-reviewed journals and presented their findings at international conferences, until Agent-based Modeling of Tax Evasion there has been no authoritative, single-source guide to state-of-the-art agent-based tax evasion modeling techniques and technologies. Featuring contributions from distinguished experts in the field from around the globe, Agent-Based Modeling of Tax Evasion provides in-depth coverage of an array of field tested agent-based tax evasion models. Models are presented in a unified format so as to enable readers to systematically work their way through the various modeling alternatives available to them. Three main components of each agent-based model are explored in accordance with the Overview, Design Concepts, and Details (ODD) protocol, each section of which contains several sub elements that help to illustrate the model clearly and that assist readers in replicating the modeling results described. Presents models in a unified and structured manner to provide a point of reference for readers interested in agent-based modeling of tax evasion Explores the theoretical aspects and diversity of agent-based modeling through the example of tax evasion Provides an overview of the characteristics of more than thirty agent-based tax evasion frameworks Functions as a solid foundation for lectures and seminars on agent-based modeling of tax evasion The only comprehensive treatment of agent-based tax evasion models and their applications, this book is an indispensable working resource for practitioners and tax evasion modelers both in the agent-based computational domain and using other methodologies. It is also an excellent pedagogical resource for teaching tax evasion modeling and/or agent-based modeling generally.}, language = {en} } @misc{SeiboldCapraraGrillietal., author = {Seibold, G{\"o}tz and Caprara, Sergio and Grilli, Marco and Raimondi, Roberto}, title = {On the Evaluation of the Spin Galvanic Effect in Lattice Models with Rashba Spin-Orbit Coupling}, series = {Condensed matter}, volume = {3}, journal = {Condensed matter}, number = {33}, issn = {2410-3896}, doi = {10.3390/condmat3030022}, pages = {1 -- 10}, abstract = {The spin galvanic effect (SGE) describes the conversion of a non-equilibrium spin polarization into a charge current and has recently attracted renewed interest due to the large conversion efficiency observed in oxide interfaces. An important factor in the SGE theory is disorder which ensures the stationarity of the conversion. Through this paper, we propose a procedure for the evaluation of the SGE on disordered lattices which can also be readily implemented for multiband systems. We demonstrate the performance of the method for a single-band Rashba model and compare our results with those obtained within the self-consistent Born approximation for a continuum model.}, language = {en} } @inproceedings{SeiboldCapraraRaimondi, author = {Seibold, G{\"o}tz and Caprara, Sergio and Raimondi, Roberto}, title = {Theory of charge-spin conversion at oxide interfaces: the inverse spin-galvanic effect}, series = {Spintronics XI, SPIE Nanoscience + Engineering, 19-23 August 2018, San Diego, California, United States}, booktitle = {Spintronics XI, SPIE Nanoscience + Engineering, 19-23 August 2018, San Diego, California, United States}, editor = {Drouhin, Henri-Jean and Wegrowe, Jean-Eric and Razeghi, Manijeh and Jaffr{\`e}s, Henri}, publisher = {Spie}, address = {Bellingham, USA}, doi = {10.1117/12.2319592}, abstract = {We evaluate the non-equilibrium spin polarization induced by an applied electric field for a tight-binding model of electron states at oxides interfaces in LAO/STO heterostructures. By a combination of analytic and numerical approaches we investigate how the spin texture of the electron eigenstates due to the interplay of spin-orbit coupling and inversion asymmetry determines the sign of the induced spin polarization as a function of the chemical potential or band filling, both in the absence and presence of local disorder. With the latter, we find that the induced spin polarization evolves from a non monotonous behavior at zero temperature to a monotonous one at higher temperature. Our results may provide a sound framework for the interpretation of recent experiments.}, language = {en} } @misc{MartensBillSeibold, author = {Martens, Christian and Bill, Andreas and Seibold, G{\"o}tz}, title = {Phase separation and proximity effects in itinerant ferromagnet/superconductor heterostructures}, series = {Physical Review B}, volume = {98}, journal = {Physical Review B}, number = {17}, issn = {2469-9969}, doi = {10.1103/PhysRevB.98.174513}, pages = {10}, abstract = {Heterostructures made of itinerant ferromagnets and superconductors are studied. In contrast to most previous models, ferromagnetism is not enforced by an effective Zeeman field but induced in a correlated single-band model (CSBM) that displays itinerant ferromagnetism as a mean-field ground state. In this model superconductivity and magnetism are both calculated self-consistently. We calculate the magnitude of the magnetization, the superconducting correlations, and variations of the charge density self-consistently for a superconducting-magnetic bilayer by solving the Bogoliubov-de Gennes equations on a two-dimensional lattice. We determine all three quantities as a function of the Coulomb repulsion U and the ferromagnetic exchange interaction J. The CSBM displays a variety of features not present in the Zeeman exchange model—for example, the occurrence of electronic phase separation and the competition of magnetic and superconducting orders far away from the interface.}, language = {en} } @misc{MiaoFumagalliRossietal., author = {Miao, Hu and Fumagalli, Roberto and Rossi, M. and Lorenzana, Jos{\´e} and Seibold, G{\"o}tz and Yakhou-Harris, Flora and Kummer, K. and Brookes, Nicholas B. and Gu, G. D. and Braicovich, Lucio and Ghiringhelli, Giacomo Claudio and Dean, M. P. M.}, title = {Formation of Incommensurate Charge Density Waves in Cuprates}, series = {Physical Review X}, volume = {9}, journal = {Physical Review X}, number = {3}, issn = {2160-3308}, doi = {10.1103/PhysRevX.9.031042}, pages = {031042-1 -- 031042-11}, abstract = {Although charge density waves (CDWs) are omnipresent in cuprate high-temperature superconductors, they occur at significantly different wave vectors, confounding efforts to understand their formation mechanism. Here, we use resonant inelastic x-ray scattering to investigate the doping- and temperature-dependent CDW evolution in La₂₋ₓBaₓCuO₄ (x=0.115-0.155). We discover that the CDW develops in two stages with decreasing temperature. A precursor CDW with a quasicommensurate wave vector emerges first at high temperature. This doping-independent precursor CDW correlation originates from the CDW phase mode coupled with a phonon and "seeds" the low-temperature CDW with a strongly doping-dependent wave vector. Our observation reveals the precursor CDW and its phase mode as the building blocks of the highly intertwined electronic ground state in the cuprates.}, language = {en} } @techreport{NoellSeiboldKrebs, author = {Noell, M. and Seibold, G{\"o}tz and Krebs, Andreas}, title = {Excitations in disordered superconductors: Inclusion of long-range Coulomb interactions}, publisher = {HLRN}, address = {Berlin}, isbn = {978-3-00-063360-7}, pages = {269}, language = {en} } @misc{NoatschkMartensSeibold, author = {Noatschk, Katharina and Martens, Christian and Seibold, G{\"o}tz}, title = {Time-Dependent Gutzwiller Approximation: Theory and Applications}, series = {Journal of Superconductivity and Novel Magnetism}, volume = {33}, journal = {Journal of Superconductivity and Novel Magnetism}, number = {8}, doi = {10.1007/s10948-019-05406-z}, pages = {2389 -- 2393}, abstract = {The time-dependent Gutzwiller approximation is rederived on the basis of a variational wave function which is a direct product of a Slater determinant and a coherent state. The latter can be related to the slave-boson formulation by Kotliar and Ruckenstein, and our approach offers a convenient way to generalize the theory towards the implementation of symmetry-broken states and the study of non-equilibrium phenomena. We discuss the concept with regard to applications in the linear response limit and for quenched antiferromagnetic order for which we evaluate the optical conductivity in non-equilibrium situations.}, language = {en} } @misc{SeiboldLorenzana, author = {Seibold, G{\"o}tz and Lorenzana, Jose}, title = {Nonequilibrium dynamics from BCS to the bosonic limit}, series = {Physical Review B}, volume = {102}, journal = {Physical Review B}, number = {14}, issn = {2469-9969}, doi = {10.1103/PhysRevB.102.144502}, pages = {15}, abstract = {Within the time-dependent Gutzwiller approximation applied to the negative-U Hubbard model, we investigate the dynamics of a superconductor after an interaction quench for different values of the final interaction from weak to strong coupling. The equilibrium BCS-BEC crossover becomes a sharp transition in the out-of-equilibrium dynamics between weak- and strong-coupling dynamical phases. Two different frequencies (ΩJ<ΩU) dominate the order parameter dynamics. In the weak coupling phase, ΩJ follows twice the asymptotic average value of the gap (ΩJ≈2Δ∞) and ΩU is much larger but hardy visible in the anomalous density. At long times the BCS dynamics is recovered but surprisingly differences remain during the transient phase. In the strong coupling phase, the dynamics decouples from the asymptotic value of the order parameter except at exactly half filling and close to the dynamical transition where ΩU≈2Δ∞. The out-of-equilibrium transient spectral density and optical conductivity are presented and discussed in relation to pump probe experiments. Both ΩJ and ΩU give rise to a complex structure of self-driven slow Rabi oscillations which are visible in the nonequilibrium optical conductivity where also sidebands appear due to the modulation of the double occupancy by superconducting amplitude oscillations. Analogous results apply to CDW and SDW systems. Our results show that in systems with long coherence times, pump-probe experiments allow us to characterize the regime (BCS vs preformed pairs) through very specific out-of-equilibrium fingerprints.}, language = {en} } @misc{BillHizhnyakovKremeretal., author = {Bill, Andreas and Hizhnyakov, Vladimir and Kremer, Reinhard K. and Seibold, G{\"o}tz and Shelkan, Aleksander and Sherman, Aleksei}, title = {Phase Separation and Pairing Fluctuations in Oxide Materials}, series = {Condensed Matter}, volume = {5}, journal = {Condensed Matter}, number = {4}, issn = {2410-3896}, doi = {10.3390/condmat5040065}, pages = {23}, abstract = {The microscopic mechanism of charge instabilities and the formation of inhomogeneous states in systems with strong electron correlations is investigated. We demonstrate that within a strong coupling expansion the single-band Hubbard model shows an instability towards phase separation and extend the approach also for an analysis of phase separation in the Hubbard-Kanamori hamiltonian as a prototypical multiband model. We study the pairing fluctuations on top of an inhomogeneous stripe state where superconducting correlations in the extended s-wave and d-wave channels correspond to (anti)bound states in the two-particle spectra. Whereas extended s-wave fluctuations are relevant on the scale of the local interaction parameter U, we find that d-wave fluctuations are pronounced in the energy range of the active subband which crosses the Fermi level. As a result, low energy spin and charge fluctuations can transfer the d-wave correlations from the bound states to the low energy quasiparticle bands. Our investigations therefore help to understand the coexistence of stripe correlations and d-wave superconductivity in cuprates.}, language = {en} } @misc{SeiboldArpaiaYingYingetal., author = {Seibold, G{\"o}tz and Arpaia, Riccardo and Ying Ying, Peng and Fumagalli, Roberto and Braicovich, Lucio and Di Castro, Carlo and Grilli, Marco and Ghiringhelli, Giacomo Claudio and Caprara, Sergio}, title = {Strange metal behaviour from charge density fluctuations in cuprates}, series = {Communications Physics}, volume = {4}, journal = {Communications Physics}, issn = {2399-3650}, doi = {10.1038/s42005-020-00505-z}, pages = {1 -- 6}, abstract = {Besides the mechanism responsible for high critical temperature superconductivity, the grand unresolved issue of the cuprates is the occurrence of a strange metallic state above the so-called pseudogap temperature T*. Even though such state has been successfully described within a phenomenological scheme, the so-called Marginal Fermi-Liquid theory, a microscopic explanation is still missing. However, recent resonant X-ray scattering experiments identified a new class of charge density fluctuations characterized by low characteristic energies and short correlation lengths, which are related to the well-known charge density waves. These fluctuations are present over a wide region of the temperature-vs-doping phase diagram and extend well above T*. Here we investigate the consequences of charge density fluctuations on the electron and transport properties and find that they can explain the strange metal phenomenology. Therefore, charge density fluctuations are likely the long-sought microscopic mechanism underlying the peculiarities of the metallic state of cuprates.}, language = {en} } @misc{SeiboldUdinaCastellanietal., author = {Seibold, G{\"o}tz and Udina, Mattia and Castellani, Claudio and Benfatto, Lara}, title = {Third harmonic generation from collective modes in disordered superconductors}, series = {Physical Review B}, volume = {103}, journal = {Physical Review B}, number = {1}, doi = {10.1103/PhysRevB.103.014512}, pages = {19}, abstract = {Recent experiments with strong THz fields in both conventional and unconventional superconductors have clearly evidenced a marked third-harmonic generation below the superconducting temperature Tc. Its interpretation challenged substantial theoretical work aimed at establishing the relative efficiency of quasiparticle excitations and collective modes in triggering such a resonant response. Here we compute the nonlinear current by implementing a time-dependent Bogoljubov-de Gennes approach, with the twofold aim to account nonperturbatively for the effect of local disorder, and to include the contribution of all collective modes, i.e., superconducting amplitude (Higgs) and phase fluctuations, and charge fluctuations. We show that, in agreement with previous work, already at small disorder the quasiparticle response is dominated by paramagnetic effects. We further demonstrate that paramagnetic processes mediate also the response of all collective modes, with a substantial contribution of charge/phase fluctuations. These processes, which have been overlooked so far, turn out to dominate the third-order current at strong disorder. In addition, we show that disorder strongly influences the polarization dependence of the nonlinear response, with a marked difference between the clean and the disordered case. Our results are particularly relevant for recent experiments in cuprates, whose band structure is in a first approximation reproduced by our lattice model.}, language = {en} }