@misc{SeiboldGrilliLorenzana, author = {Seibold, G{\"o}tz and Grilli, Marco and Lorenzana, Jos{\´e}}, title = {Model of Quasiparticles Coupled to a Frequency-Dependent Charge-DensityWave Order Parameter in Cuprate Superconductors}, 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{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} } @misc{SeiboldLorenzana, author = {Seibold, G{\"o}tz and Lorenzana, Jos{\´e}}, title = {Diagonal stripes in the spin glass phase of cuprates}, series = {Physica : C}, volume = {470}, journal = {Physica : C}, number = {Suppl. 1}, pages = {245 -- 246}, 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{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} } @misc{SeiboldGrilliLorenzana, author = {Seibold, G{\"o}tz and Grilli, Marco and Lorenzana, Jos{\´e}}, title = {Dynamical charge and spin density wave scattering in cuprate superconductors}, 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} } @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{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{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{GrilliSeiboldDiCioloetal., author = {Grilli, Marco and Seibold, G{\"o}tz and Di Ciolo, A. and Lorenzana, Jos{\´e}}, title = {Fermi surface dichotomy in systems with fluctuating order}, series = {Physical Review B}, volume = {79}, journal = {Physical Review B}, issn = {1550-235X}, pages = {125111}, 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} } @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} } @article{SeiboldSigmund, author = {Seibold, G{\"o}tz and Sigmund, Ernst}, title = {Differences between one and multiband Hubbard models}, 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{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} } @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{SeiboldLorenzana, author = {Seibold, G{\"o}tz and Lorenzana, Jos{\´e}}, title = {Calculation of incommensurability and spin excitations of diagonal stripes in underdoped lanthanum cuprates}, series = {Physical Review B}, volume = {80}, journal = {Physical Review B}, number = {1}, issn = {1550-235X}, pages = {012509}, language = {en} } @article{SeiboldVarlamov, author = {Seibold, G{\"o}tz and Varlamov, Sergej}, title = {Spectral properties of incommensurate CDW scattering in cuprates}, 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{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} } @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} } @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} } @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{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{GuentherSeiboldLorenzana, author = {G{\"u}nther, Falk and Seibold, G{\"o}tz and Lorenzana, Jos{\´e}}, title = {Stability of ferromagnetism within the time-dependent Gutzwiller approximation for the 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} } @article{SeiboldLorenzanaColdea, author = {Seibold, G{\"o}tz and Lorenzana, Jos{\´e} and Coldea, Radu}, title = {Sum rules and missing spectral weight in magnetic neutron scattering in the cuprates}, language = {en} } @article{SeiboldBeccaLorenzana, author = {Seibold, G{\"o}tz and Becca, Federico and Lorenzana, Jos{\´e}}, title = {Theory of antibound states in partially filled narrow band systems}, 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{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} } @article{SeiboldLorenzana, author = {Seibold, G{\"o}tz and Lorenzana, Jos{\´e}}, title = {Magnetic excitations in the stripe phase of the Hubbard model}, 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} } @misc{WahlbergArpaiaSeiboldetal., author = {Wahlberg, Eric and Arpaia, Riccardo and Seibold, G{\"o}tz and Rossi, Matteo and Fumagalli, Roberto and Trabaldo, Edoardo and Brookes, Nicholas B. and Braicovich, Lucio and Caprara, Sergio and Lombardi, Floriana and Gran, Ulf and Ghiringhelli, Giacomo Claudio and Bauch, Thilo}, title = {Restored strange metal phase through suppression of charge density waves in underdoped YBa2Cu3O7-δ}, series = {Science}, volume = {373}, journal = {Science}, number = {6562}, doi = {10.1126/science.abc8372}, pages = {1506 -- 1510}, abstract = {The normal state of optimally doped cuprates is dominated by the "strange metal" phase that shows a linear temperature (T) dependence of the resistivity persisting down to the lowest T. For underdoped cuprates, this behavior is lost below the pseudogap temperature T*, where charge density waves (CDWs), together with other intertwined local orders, characterize the ground state. We found that the T-linear resistivity of highly strained, ultrathin, underdoped YBa2Cu3O7-δ films is restored when the CDW amplitude, detected by resonant inelastic x-ray scattering, is suppressed. This observation suggests an intimate connection between the onset of CDWs and the departure from T-linear resistivity in underdoped cuprates. Our results illustrate the potential of using strain control to manipulate the ground state of quantum materials.}, language = {en} } @misc{GrilliDiCastroMirarchietal., author = {Grilli, Marco and Di Castro, Carlo and Mirarchi, Giovanni and Seibold, G{\"o}tz and Caprara, Sergio}, title = {Dissipative Quantum Criticality as a Source of Strange Metal Behavior}, series = {Symmetry}, volume = {15}, journal = {Symmetry}, number = {3}, issn = {2073-8994}, doi = {10.3390/sym15030569}, abstract = {The strange metal behavior, usually characterized by a linear-in-temperature (T) resistivity, is a still unsolved mystery in solid-state physics. It is often associated with the proximity to a quantum critical point (a second order transition at temperature T=0, leading to a broken symmetry phase) focusing on the related divergent order parameter correlation length. Here, we propose a paradigmatic shift, focusing on a divergent characteristic time scale due to a divergent dissipation acting on the fluctuating critical modes while their correlation length stays finite. To achieve a divergent dissipation, we propose a mechanism based on the coupling between a local order parameter fluctuation and electron density diffusive modes that accounts both for the linear-in-T resistivity and for the logarithmic specific heat versus temperature ratio CV/T∼log(1/T), down to low temperatures.}, 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{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{LorenzanaSeibold, author = {Lorenzana, Jose and Seibold, G{\"o}tz}, title = {Long-Lived Higgs Modes in Strongly Correlated Condensates}, series = {Physical Review Letters}, volume = {132}, journal = {Physical Review Letters}, number = {2}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.132.026501}, pages = {026501-1 -- 026501-8}, abstract = {We investigate order parameter fluctuations in the Hubbard model within a time-dependent Gutzwiller approach. While in the weak coupling limit we find that the amplitude fluctuations are short-lived due to a degeneracy with the energy of the edge of the quasiparticle continua (and in agreement with Hartree-Fock+RPA theory), these are shifted below the edge upon increasing the interaction. Our calculations therefore predict undamped amplitude (Higgs) oscillations of the order parameter in strongly coupled superconductors, cold atomic fermion condensates, and strongly interacting charge- and spin-density wave systems. We propose an experimental realization for the detection of the spin-type Higgs mode in undoped cuprates and related materials where, due to the Dzyaloshinsky-Moriya interaction, it can couple to an out-of-plane ferromagnetic excitation that is visible via the Faraday effect.}, language = {en} } @misc{MirarchiGrilliSeiboldetal., author = {Mirarchi, Giovanni and Grilli, Marco and Seibold, G{\"o}tz and Caprara, Sergio}, title = {The Shrinking Fermi Liquid Scenario for Strange-Metal Behavior from Overdamped Optical Phonons}, series = {Condensed Matter}, volume = {9}, journal = {Condensed Matter}, number = {1}, issn = {2410-3896}, doi = {10.3390/condmat9010014}, pages = {1 -- 13}, abstract = {We discuss how the interaction of electrons with an overdamped optical phonon can give rise to a strange-metal behavior over extended temperature and frequency ranges. Although the mode has a finite frequency, an increasing damping shifts spectral weight to progressively lower energies so that despite the ultimate Fermi liquid character of the system at the lowest temperatures and frequencies, the transport and optical properties of the electron system mimic a marginal Fermi liquid behavior. Within this shrinking Fermi liquid scenario, we extensively investigate the electron self-energy in all frequency and temperature ranges, emphasizing similarities and differences with respect to the marginal Fermi liquid scenario.}, 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} } @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{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} } @inproceedings{ShelkanSigmundHizhnyakovetal., author = {Shelkan, Aleksander and Sigmund, Ernst and Hizhnyakov, Vladimir and Seibold, G{\"o}tz}, title = {Free and spin-polaron states in high-Tc superconductor}, series = {Proceedings of the NATO Advanced Research Workshop on Colossal Magnetoresistance and Vibronic Interactions and the XVth International Jahn-Teller Symposium on Vibronic Interactions in Crystals and Molecules, Boston, August 16 - 22, 2000}, booktitle = {Proceedings of the NATO Advanced Research Workshop on Colossal Magnetoresistance and Vibronic Interactions and the XVth International Jahn-Teller Symposium on Vibronic Interactions in Crystals and Molecules, Boston, August 16 - 22, 2000}, editor = {Kaplan, Michael D.}, publisher = {Kluwer}, address = {Dordrecht [u.a.]}, isbn = {1-402-00044-8}, pages = {349 -- 356}, 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{SeiboldLorenzana, author = {Seibold, G{\"o}tz and Lorenzana, Jos{\´e}}, title = {Magnetic fluctuations of stripes in the high temperature cuprate superconductors}, 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{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} } @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} } @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} }