TY - JOUR A1 - Müller, Sebastian A1 - Seibold, Götz A1 - Schmeißer, Dieter ED - Vierhaus, Heinrich Theodor T1 - Preparation and Characterization of TiO2 Thin Films and Cr and Co Doped TiO2 Thin Films Y1 - 2007 ER - TY - JOUR A1 - Seibold, Götz A1 - Lorenzana, José T1 - Doping dependence of spin excitations in the stripe phase of high-Tc superconductors Y1 - 2006 ER - TY - GEN A1 - Seibold, Götz A1 - Di Castro, Carlo A1 - Grilli, Marco A1 - Lorenzana, José T1 - Spin excitations of ferronematic order in underdoped cuprate superconductors T2 - Scientific reports N2 - 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. Y1 - 2014 UR - http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4060504/ U6 - https://doi.org/10.1038/srep05319 SN - 2045-2322 IS - 4 SP - 5319 ER - TY - GEN A1 - Markiewicz, Richard S. A1 - Lorenzana, José A1 - Seibold, Götz T1 - Gutzwiller magnetic phase diagram of the undoped $ t- t' -U $ Hubbard model Y1 - 2010 ER - TY - GEN A1 - Bünemann, Jörg A1 - Capone, Michael A1 - Lorenzana, José A1 - Seibold, Götz T1 - Linear-response dynamics from the time-dependent Gutzwiller approximation T2 - New Journal of Physics N2 - 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. Y1 - 2013 UR - http://iopscience.iop.org/article/10.1088/1367-2630/15/5/053050 SN - 1367-2630 VL - 15 ER - TY - GEN A1 - Seibold, Götz A1 - Grilli, Marco A1 - Lorenzana, José T1 - Stripes in cuprate superconductors: Excitations and dynamic dichotomy T2 - Physica C: Superconductivity N2 - 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. Y1 - 2012 UR - http://www.sciencedirect.com/science/article/pii/S0921453412001864 U6 - https://doi.org/10.1016/j.physc.2012.03.072 SN - 0921-4534 VL - 481 SP - 132 EP - 145 ER - TY - GEN A1 - Hizhnyakov, Vladimir A1 - Seibold, Götz T1 - Nanoscale phase separation in cuprate superconductors T2 - Physica C: Superconductivity and its Applications N2 - 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. In this contribution we review the particular contribution of the Stuttgart-Tartu-Cottbus group to this field, which has been largely stimulated by intense discussion with K. Alex Müller. The original scenario, which was based on the formation of a percolative electronic network, is substantiated by a microscopic analysis of the clustering of magnetic polarons within the one-band Hubbard model. KW - Cuprates KW - Superconductors KW - Phase separation KW - Electronic inhomogeneities Y1 - 2023 UR - https://www.sciencedirect.com/science/article/pii/S0921453423001004 U6 - https://doi.org/10.1016/j.physc.2023.1354309 SN - 1873-2143 VL - 612 SP - 1 EP - 7 ER - TY - GEN A1 - Seibold, Götz A1 - Benfatto, Lara A1 - Castellani, Claudio A1 - Lorenzana, José T1 - Current Correlations in Strongly Disordered Superconductors T2 - Journal of Superconductivity and Novel Magnetism Y1 - 2016 UR - http://link.springer.com/article/10.1007%2Fs10948-015-3300-6 U6 - https://doi.org/10.1007/s10948-015-3300-6 VL - 29 IS - 3 SP - 577 EP - 580 ER - TY - JOUR A1 - Seibold, Götz A1 - Lorenzana, José T1 - Stability of metallic stripes in the extended one-band Hubbard model Y1 - 2004 ER - TY - GEN A1 - Markiewicz, Richard S. A1 - Lorenzana, José A1 - Seibold, Götz A1 - Bansil, Arun T1 - Short range smectic order driving long range nematic order: example of cuprates T2 - Scientific reports Y1 - 2016 UR - http://www.nature.com/articles/srep19678 U6 - https://doi.org/10.1038/srep19678 SN - 2045-2322 VL - 6 SP - 19678 ER - TY - JOUR A1 - Günther, Falk A1 - Seibold, Götz T1 - Time-dependent Gutzwiller theory of pair fluctuations in the Hubbard model Y1 - 2007 ER - TY - GEN A1 - Benfatto, Lara A1 - Castellani, Claudio A1 - Seibold, Götz T1 - Linear and nonlinear current response in disordered d-wave superconductors T2 - Physical Review B N2 - We present a detailed theoretical investigation of the linear and nonlinear optical response in a model system for a disordered d-wave superconductor. By evaluating the quasiparticle contribution (BCS response) we show that for both quantities the gap symmetry considerably changes the paradigm of the optical response as compared to the conventional s-wave case. For what concerns the linear response our findings agree with previous work showing that in strongly disordered d-wave superconductors a large fraction of uncondensed spectral weight survives below Tc, making the optical absorption around the gap-frequency scale almost unchanged with respect to the normal state. Our numerical results are in excellent quantitative agreement with experiments in overdoped cuprates. In the nonlinear regime we focus on the third-harmonic generation (THG), finding that, as already established for the s-wave case, in general a large THG is triggered by disorder-activated paramagnetic processes. However, in the d-wave case the BCS response is monotonously increasing in frequency, losing any signature of THG enhancement when the THz pump frequency ω matches the gap maximum Δ, a hallmark of previous experiments in conventional s-wave superconductors. Our findings, along with the mild polarization dependence of the response, provide an explanation for recent THG measurements in cuprates, setting the framework for the theoretical understanding of nonlinear effects in unconventional cuprates. KW - Superconducting order parameter KW - Superfluid density KW - High-temperature superconductors KW - Superconductivity KW - Drude model KW - Numerical techniques KW - Reflectivity KW - Terahertz spectroscopy Y1 - 2023 UR - https://journals.aps.org/prb/abstract/10.1103/PhysRevB.108.134508 U6 - https://doi.org/10.1103/PhysRevB.108.134508 SN - 2469-9969 SN - 2469-9950 VL - 108 SP - 134508-1 EP - 134508-15 ER - TY - GEN A1 - Seibold, Götz A1 - Castellani, Claudio A1 - Di Castro, Carlo A1 - Grilli, Marco T1 - Fermi surface and photoemission lineshape of incommensurate CDW systems Y1 - 2000 ER - TY - JOUR A1 - Sigmund, Ernst A1 - Hizhnyakov, Vladimir A1 - Seibold, Götz T1 - Phase-Separation in High-Tc Superconductors JF - Physica C : Superconductivity Y1 - 1994 SN - 0921-4534 VL - Vol. 235–240 IS - 1 SP - 253 EP - 256 ER - TY - JOUR A1 - Seibold, Götz A1 - Grilli, Marco A1 - Lorenzana, José T1 - Checkerboard and stripe inhomogeneities in cuprates JF - Physical review B Y1 - 2007 SN - 1550-235X VL - 75 IS - 10 SP - 10050(R) ER - TY - GEN A1 - Ugenti, S. A1 - Cini, M. A1 - Seibold, Götz A1 - Lorenzana, José A1 - Perfetto, E. A1 - Stefanucci, G. T1 - Particle-particle response function as a probe for electronic correlations in the p-d Hubbard model Y1 - 2010 ER - TY - GEN A1 - Seibold, Götz A1 - Varlamov, Sergej T1 - Effect of incommensurate charge-density wave scattering on theelectronic structure of high-Tc cuprates (I) T2 - Journal of Superconductivity Y1 - 2002 SN - 0896-1107 VL - 15 IS - 5 SP - 387 EP - 388 ER - TY - CHAP A1 - Seibold, Götz A1 - Castellani, Claudio A1 - Di Castro, Carlo A1 - Grilli, Marco ED - Bianconi, Antonio ED - Saini, Naurang L. T1 - Domain wall structures in the two-dimensional Hubbard modelwith long-range Coulomb interaction T2 - Stripes and Related Phenomena Y1 - 2000 SN - 0-306-46419-5 U6 - https://doi.org/10.1007/0-306-47100-0_18 SP - 151 EP - 157 PB - Kluwer Academic Plenum CY - New York ER - TY - GEN A1 - Seibold, Götz A1 - Grilli, Marco A1 - Lorenzana, José T1 - Model of Quasiparticles Coupled to a Frequency-Dependent Charge-DensityWave Order Parameter in Cuprate Superconductors Y1 - 2009 ER - TY - GEN A1 - Seibold, Götz A1 - Markiewicz, Richard S. A1 - Lorenzana, José T1 - Stripes with Spin Canting in the Three-Band Hubbard Model T2 - Journal of Superconductivity and Novel Magnetism N2 - 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. KW - Stripes KW - Spirals KW - High-temperature superconductors Y1 - 2013 UR - http://link.springer.com/article/10.1007/s10948-012-1701-3 U6 - https://doi.org/10.1007/s10948-012-1701-3 SN - 1557-1939 SN - 1557-1947 VL - 26 IS - 1 SP - 49 EP - 52 ER - TY - GEN A1 - Seibold, Götz A1 - Castellani, Claudio A1 - Di Castro, Carlo A1 - Grilli, Marco T1 - Striped phases in the two-dimensional Hubbard model with long-rangeCoulomb interaction Y1 - 1998 ER - TY - GEN A1 - Seibold, Götz A1 - Lorenzana, José T1 - Diagonal stripes in the spin glass phase of cuprates T2 - Physica : C Y1 - 2009 N1 - Proceedings of the 9th International Conference on Materials andMechanisms of Superconductivity VL - 470 IS - Suppl. 1 SP - 245 EP - 246 ER - TY - GEN A1 - Seibold, Götz A1 - Markiewicz, Richard S. A1 - Lorenzana, José T1 - Magnetic Structure of Electronic Inhomogeneities in Cuprates: Competition between Stripes and Spirals T2 - Acta Physica Polonica A N2 - 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. Y1 - 2012 UR - https://www.researchgate.net/publication/230739012_Magnetic_Structure_of_Electron ic_Inhomogeneities_in_Cuprates_Competition_between_Stripes_and_Spirals SN - 1898-794X VL - 121 IS - 5-6 SP - 1019 EP - 1021 ER - TY - GEN A1 - Seibold, Götz A1 - Castellani, Claudio A1 - Di Castro, Carlo A1 - Grilli, Marco ED - Barnes, Stewart E. T1 - Role of the long-range Coulomb interaction on the formation of striped phases in the two-dimensional Hubbard model T2 - High temperature superconductivity, Coral Gables, Florida, January 1999 Y1 - 1999 SN - 1-56396-880-0 U6 - https://doi.org/10.1063/1.59651 PB - AIP Publishing CY - Melville, New York ER - TY - GEN A1 - Seibold, Götz A1 - Grilli, Marco A1 - Lorenzana, José T1 - Dynamical charge and spin density wave scattering in cuprate superconductors Y1 - 2010 ER - TY - GEN A1 - Capati, Matteo A1 - Caprara, Sergio A1 - Di Castro, Carlo A1 - Grilli, Marco A1 - Seibold, Götz A1 - Lorenzana, José T1 - Electronic polymers and soft-matter-like broken symmetries in underdoped cuprates T2 - Nature Communications N2 - 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. KW - Molecular electronics KW - Polymers KW - Superconducting properties and materials Y1 - 2015 UR - http://www.nature.com/articles/ncomms8691 U6 - https://doi.org/doi:10.1038/ncomms8691 SN - 2041-1723 VL - 6 SP - 7691 ER - TY - GEN A1 - Cea, Tommaso A1 - Bucheli, Daniel A1 - Seibold, Götz A1 - Benfatto, Lara A1 - Lorenzana, José A1 - Castellani, Claudio T1 - Optical excitation of phase modes in strongly disordered superconductors T2 - Physical Review B N2 - 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. Y1 - 2014 UR - http://journals.aps.org/prb/abstract/10.1103/PhysRevB.89.174506 U6 - https://doi.org/10.1103/PhysRevB.89.174506 SN - 2469-9969 VL - 89 SP - 174506 ER - TY - GEN A1 - Seibold, Götz A1 - Benfatto, Lara A1 - Castellani, Claudio A1 - Lorenzana, José T1 - Amplitude, density, and current correlations of strongly disordered superconductors T2 - Physical Review B N2 - 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. Y1 - 2015 UR - http://journals.aps.org/prb/abstract/10.1103/PhysRevB.92.064512 U6 - https://doi.org/10.1103/PhysRevB.92.064512 SN - 2469-9969 VL - 92 IS - 6 SP - 064512 ER - TY - GEN A1 - Markiewicz, Richard S. A1 - Lorenzana, José A1 - Seibold, Götz A1 - Bansil, Arun T1 - Competing phases on the cuprates: Charge vs spin order Y1 - 2011 ER - TY - GEN A1 - Grilli, Marco A1 - Seibold, Götz A1 - Di Ciolo, A. A1 - Lorenzana, José T1 - Fermi surface dichotomy in systems with fluctuating order T2 - Physical Review B Y1 - 2009 SN - 1550-235X VL - 79 SP - 125111 ER - TY - JOUR A1 - Seibold, Götz A1 - Becca, Federico A1 - Rubin, P. A1 - Lorenzana, José T1 - Time-dependent Gutzwiller theory of magnetic excitations in the Hubbard model Y1 - 2004 ER - TY - GEN A1 - Seibold, Götz A1 - Grilli, Marco A1 - Lorenzana, José T1 - Influence of correlations on transitive electron-phonon couplings in cuprate superconductors Y1 - 2011 ER - TY - JOUR A1 - Seibold, Götz A1 - Sigmund, Ernst T1 - Differences between one and multiband Hubbard models Y1 - 1995 ER - TY - GEN A1 - Caprara, Sergio A1 - Grilli, Marco A1 - Di Castro, Carlo A1 - Seibold, Götz T1 - Pseudogap and (An)isotropic Scattering in the Fluctuating Charge-Density Wave Phase of Cuprates T2 - Journal of Superconductivity and Novel Magnetism N2 - 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). KW - Charge-density waves KW - High-Tc superconducting cuprates KW - Anisotropic scattering Y1 - 2017 UR - http://link.springer.com/article/10.1007/s10948-016-3775-9 U6 - https://doi.org/10.1007/s10948-016-3775-9 SN - 1557-1939 SN - 1557-1947 VL - 30 IS - 1 SP - 25 EP - 30 ER - TY - GEN A1 - Martens, Christian A1 - Bill, Andreas A1 - Seibold, Götz T1 - Phase separation and proximity effects in itinerant ferromagnet/superconductor heterostructures T2 - Physical Review B N2 - 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. KW - charge order KW - Exchange interaction KW - Ferromagnetism KW - Local density of states KW - Microphase separation KW - Proximity effect KW - Superconducting order parameter Y1 - 2018 U6 - https://doi.org/10.1103/PhysRevB.98.174513 SN - 2469-9969 SN - 1095-3795 VL - 98 IS - 17 ER - TY - CHAP A1 - Bill, Andreas A1 - Hizhnyakov, Vladimir A1 - Seibold, Götz ED - Bussmann-Holder, Annette ED - Keller, Hugo ED - Bianconi, Antonio T1 - Electronic Phase Separation and Electron–Phonon Coupling in Cuprate Superconductors T2 - High-Tc Copper Oxide Superconductors and Related Novel Materials N2 - 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. KW - Strongly Correlated Systems KW - Optical and Electronic Materials KW - Nanochemistry KW - Ceramics KW - Spectroscopy and Microscopy KW - Superconductivity KW - Glass KW - Composites KW - Natural Materials Y1 - 2017 UR - http://link.springer.com/chapter/10.1007/978-3-319-52675-1_1 SN - 978-3-319-52674-4 SN - 978-3-319-52675-1 U6 - https://doi.org/10.1007/978-3-319-52675-1_1 SP - 1 EP - 14 PB - Springer International Publishing CY - Cham ER - TY - GEN A1 - Seibold, Götz A1 - Lorenzana, José T1 - Calculation of incommensurability and spin excitations of diagonal stripes in underdoped lanthanum cuprates T2 - Physical Review B Y1 - 2009 SN - 1550-235X VL - 80 IS - 1 SP - 012509 ER - TY - JOUR A1 - Seibold, Götz A1 - Varlamov, Sergej T1 - Spectral properties of incommensurate CDW scattering in cuprates Y1 - 2003 ER - TY - GEN A1 - Markiewicz, Richard S. A1 - Seibold, Götz A1 - Lorenzana, José A1 - Bansil, Arun T1 - Gutzwiller charge phase diagram of cuprates, including electron–phonon coupling effects T2 - New Journal of Physics N2 - 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. Y1 - 2015 UR - http://iopscience.iop.org/article/10.1088/1367-2630/17/2/023074/meta U6 - https://doi.org/10.1088/1367-2630/17/2/023074 SN - 1367-2630 VL - 17 IS - 2 SP - 023074 ER - TY - GEN A1 - Seibold, Götz A1 - Benfatto, Lara A1 - Castellani, Claudio A1 - Lorenzana, José T1 - Superfluid Density and Phase Relaxation in Superconductors with Strong Disorder T2 - Physical Review Letters N2 - 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. Y1 - 2012 UR - http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.108.207004 U6 - https://doi.org/10.1103/PhysRevLett.108.207004 SN - 1092-0145 VL - 108 IS - 20 SP - 207004 ER - TY - JOUR A1 - Seibold, Götz A1 - Varlamov, Sergej T1 - Relationship between incommensurability and superconductivity in Peierls distorted charge-density-wave systems JF - Physical review : B Y1 - 1999 SN - 0556-2805 VL - 60 SP - 13056 ER - TY - JOUR A1 - Varlamov, Sergej A1 - Seibold, Götz T1 - Effective interactions in the stripe state of the two-dimensional Hubbard model Y1 - 2002 ER - TY - CHAP A1 - Seibold, Götz ED - Hokamp, Sascha ED - Gulyas, Lazlo ED - Koehler, Matthew ED - Wijesinghe, Sanith T1 - From Spins to Agents: An Econophysics Approach to Tax Evasion T2 - Agent-based Modeling of Tax Evasion: Theoretical Aspects and Computational Simulations N2 - 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. KW - General & Introductory Statistics KW - Applied Probability & Statistics Statistics for Finance" Business & Economics KW - Statistics for Finance" Business & Economics Y1 - 2018 SN - 978-1-119-15570-6 SP - 315 EP - 336 PB - Wiley CY - Weinheim ER - TY - GEN A1 - Bazart, Cécile A1 - Bonein, Aurélie A1 - Hokamp, Sascha A1 - Seibold, Götz T1 - Bahavioural Economics and Tax Evasion: Calibrating an Agent-based Econophysics Model with Experimental Tax Compliance Data T2 - Journal of Tax Administration Y1 - 2016 UR - http://jota.website/article/view/74 VL - 2 IS - 1 SP - 126 EP - 144 ER - TY - GEN A1 - Günther, Falk A1 - Seibold, Götz A1 - Lorenzana, José T1 - Stability of ferromagnetism within the time-dependent Gutzwiller approximation for the Hubbard model Y1 - 2011 ER - TY - JOUR A1 - Varlamov, Sergej A1 - Seibold, Götz T1 - Influence of the pseudogap on the superconductivity-inducedphonon renormalization in high-Tc superconductors Y1 - 2002 ER - TY - JOUR A1 - Seibold, Götz A1 - Lorenzana, José A1 - Coldea, Radu T1 - Sum rules and missing spectral weight in magnetic neutron scattering in the cuprates Y1 - 2005 ER - TY - JOUR A1 - Seibold, Götz A1 - Becca, Federico A1 - Lorenzana, José T1 - Theory of antibound states in partially filled narrow band systems Y1 - 2008 ER - TY - GEN A1 - Miao, Hu A1 - Lorenzana, José A1 - Seibold, Götz A1 - Peng, Yingying A1 - Amorese, Andrea A1 - Yakhou-Harris, Flora A1 - Kummer, Kurt A1 - Brookes, Nicholas B. A1 - Konik, R. M. A1 - Thampy, Vivek A1 - Gu, G. D. A1 - Ghiringhelli, Giacomo Claudio A1 - Braicovich, Lucio A1 - Dean, M. P. M. T1 - High-temperature charge density wave correlations in La1.875Ba0.125CuO4 without spin–charge locking T2 - Proceedings of the National Academy of Sciences of the United States of America PNAS N2 - 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. KW - charge density waves KW - stripes KW - high-temperature superconductivity KW - cuprates KW - X-rays Y1 - 2017 UR - http://www.pnas.org/content/early/2017/10/31/1708549114.abstract U6 - https://doi.org/10.1073/pnas.1708549114 SN - 1091-6490 SN - 0027-8424 VL - 114 IS - 47 SP - 12430 EP - 12435 ER - TY - GEN A1 - Schmeißer, Dieter A1 - Schmidt, Stephan A1 - Seibold, Götz A1 - Cherkashinin, Gennady A1 - Jaegermann, Wolfram T1 - Localized Gap States in LiCoO2 and their Influence on the Transport Properties in Li-Ion Batteries T2 - ECS Transactions Y1 - 2010 SN - 1938-5862 VL - 25 IS - 35 SP - 37 EP - 45 ER - TY - JOUR A1 - Seibold, Götz A1 - Lorenzana, José T1 - Magnetic excitations in the stripe phase of the Hubbard model Y1 - 2007 ER - TY - JOUR A1 - Lorenzana, José A1 - Seibold, Götz T1 - Metallic mean-field stripes, incommensurability and chemicalpotential in cuprates Y1 - 2002 ER - TY - GEN A1 - Wahlberg, Eric A1 - Arpaia, Riccardo A1 - Seibold, Götz A1 - Rossi, Matteo A1 - Fumagalli, Roberto A1 - Trabaldo, Edoardo A1 - Brookes, Nicholas B. A1 - Braicovich, Lucio A1 - Caprara, Sergio A1 - Lombardi, Floriana A1 - Gran, Ulf A1 - Ghiringhelli, Giacomo Claudio A1 - Bauch, Thilo T1 - Restored strange metal phase through suppression of charge density waves in underdoped YBa2Cu3O7–δ T2 - Science N2 - 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. KW - Cuprate superconductors KW - Charge-Density Wave Y1 - 2021 UR - https://www.science.org/doi/10.1126/science.abc8372 U6 - https://doi.org/10.1126/science.abc8372 VL - 373 IS - 6562 SP - 1506 EP - 1510 ER - TY - GEN A1 - Grilli, Marco A1 - Di Castro, Carlo A1 - Mirarchi, Giovanni A1 - Seibold, Götz A1 - Caprara, Sergio T1 - Dissipative Quantum Criticality as a Source of Strange Metal Behavior T2 - Symmetry N2 - 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. KW - strange metal behavior KW - cuprates KW - charge density fluctuations KW - diffusive modes Y1 - 2023 U6 - https://doi.org/10.3390/sym15030569 SN - 2073-8994 VL - 15 IS - 3 ER - TY - GEN A1 - Seibold, Götz A1 - Caprara, Sergio A1 - Grilli, Marco A1 - Raimondi, Roberto T1 - Inhomogeneous Rashba spin–orbit coupling and intrinsic spin-Hall effect T2 - Journal of Magnetism and Magnetic Materials N2 - 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. KW - Spin Hall effect KW - Rashba spin–orbit coupling KW - Inhomogeneity Y1 - 2016 UR - http://www.sciencedirect.com/science/article/pii/S0304885316317772 U6 - https://doi.org/10.1016/j.jmmm.2016.12.066 VL - 440 SP - 63 EP - 65 ER - TY - GEN A1 - Seibold, Götz A1 - Markiewicz, Richard S. A1 - Lorenzana, José T1 - Spin canting as a result of the competition between stripesand spirals in cuprates Y1 - 2011 ER - TY - GEN A1 - Lorenzana, Jose A1 - Seibold, Götz T1 - Long-Lived Higgs Modes in Strongly Correlated Condensates T2 - Physical Review Letters N2 - 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. KW - Magnetism KW - Quasiparticles & collective excitations KW - Spin dynamics KW - Superconducting order parameter KW - Superconductivity KW - Antiferromagnets KW - Atomic gases KW - High-temperature superconductors Y1 - 2024 UR - https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.132.026501 U6 - https://doi.org/10.1103/PhysRevLett.132.026501 SN - 0031-9007 VL - 132 IS - 2 SP - 026501-1 EP - 026501-8 ER - TY - GEN A1 - Mirarchi, Giovanni A1 - Grilli, Marco A1 - Seibold, Götz A1 - Caprara, Sergio T1 - The Shrinking Fermi Liquid Scenario for Strange-Metal Behavior from Overdamped Optical Phonons T2 - Condensed Matter N2 - 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. KW - strange-metal behavior KW - marginal Fermi liquid KW - high-temperature cuprate superconductors Y1 - 2024 UR - https://www.mdpi.com/2410-3896/9/1/14 U6 - https://doi.org/10.3390/condmat9010014 SN - 2410-3896 VL - 9 IS - 1 SP - 1 EP - 13 ER - TY - JOUR A1 - Letz, M. A1 - Seibold, Götz A1 - Sigmund, Ernst T1 - Percolative Phase-Separation-Mean Field Calculations of Spin-Polarized States in CuO2 Planes Y1 - 1994 ER - TY - GEN A1 - Seibold, Götz A1 - Caprara, Sergio A1 - Grilli, Marco A1 - Raimondi, Roberto T1 - Non-equilibrium Spin Currents in Systems with Striped Rashba Spin-Orbit Coupling T2 - Journal of Superconductivity and Novel Magnetism N2 - 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. Y1 - 2017 UR - http://link.springer.com/article/10.1007/s10948-016-3774-x U6 - https://doi.org/10.1007/s10948-016-3774-x SN - 1557-1939 VL - 30 IS - 1 SP - 123 EP - 128 ER - TY - GEN A1 - Pickhardt, Michael A1 - Seibold, Götz T1 - Income tax evasion dynamics: Evidence from an agent-based econophysics model T2 - Journal of Economic Psychology N2 - • 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. KW - Tax evasion KW - Tax compliance KW - Ising model KW - Econophysics KW - Numerical simulation Y1 - 2013 UR - http://www.sciencedirect.com/science/article/pii/S0167487013000408 U6 - https://doi.org/10.1016/j.joep.2013.01.011 SN - 0167-4870 VL - 40 SP - 147 EP - 160 ER - TY - CHAP A1 - Shelkan, Aleksander A1 - Sigmund, Ernst A1 - Hizhnyakov, Vladimir A1 - Seibold, Götz ED - Kaplan, Michael D. T1 - Free and spin-polaron states in high-Tc superconductor T2 - 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 Y1 - 2001 SN - 1-402-00044-8 SP - 349 EP - 356 PB - Kluwer CY - Dordrecht [u.a.] ER - TY - JOUR A1 - Seibold, Götz A1 - Seidel, J. A1 - Sigmund, Ernst T1 - Inhomogeneous Spin Structures in High-Tc Cuprates Y1 - 1996 ER - TY - JOUR A1 - Seibold, Götz A1 - Lorenzana, José T1 - Magnetic fluctuations of stripes in the high temperature cuprate superconductors Y1 - 2005 ER - TY - CHAP A1 - Hokamp, Sascha A1 - Seibold, Götz ED - Kaminski, Bogumil ED - Koloch, Grzegorz T1 - How Much Rationality Tolerates the Shadow Economy? – An Agent-Based Econophysics Approach T2 - Advances in social simulation : proceedings of the 9th Conference of the European Social Simulation Association N2 - 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. KW - shadow economy KW - econophysics KW - multi-agent model Y1 - 2014 UR - http://link.springer.com/chapter/10.1007/978-3-642-39829-2_11 SN - 978-3-642-39828-5 U6 - https://doi.org/10.1007/978-3-642-39829-2_11 SP - 128 PB - Springer CY - Berlin [u.a.] ER - TY - GEN A1 - Bucheli, Daniel A1 - Grilli, Marco A1 - Peronaci, F. A1 - Seibold, Götz A1 - Caprara, Sergio T1 - Phase diagrams of voltage-gated oxide interfaces with strong Rashba coupling T2 - Physical Review B N2 - 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. Y1 - 2014 UR - https://journals.aps.org/prb/abstract/10.1103/PhysRevB.89.195448 U6 - https://doi.org/10.1103/PhysRevB.89.195448 SN - 2469-9969 VL - 89 ER - TY - JOUR A1 - Seibold, Götz A1 - Letz, M. A1 - Sigmund, Ernst A1 - Hizhnyakov, Vladimir T1 - Mean-Field Theories of Spin-Cluster States in copper oxide planes Y1 - 1994 ER - TY - GEN A1 - Seibold, Götz A1 - Bucheli, Daniel A1 - Caprara, Sergio A1 - Grilli, Marco T1 - Phase separation and long-wavelength charge instabilities in spin-orbit coupled systems T2 - EPL Europhysics Letters N2 - 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. Y1 - 2015 UR - http://iopscience.iop.org/article/10.1209/0295-5075/109/17006;jsessionid=34AAE2057398BD7AE51C0C4719FC29DD.c2.iopscience.cld.iop.org U6 - https://doi.org/10.1209/0295-5075/109/17006 SN - 1286-4854 VL - 109 IS - 1 SP - 17006 ER - TY - JOUR A1 - Eremin, M. A1 - Varlamov, Sergej A1 - Eremenin, I. A1 - Seibold, Götz T1 - Influence of incommensurability on SDW and CDW amplitudes in underdoped cuprates Y1 - 2000 ER - TY - JOUR A1 - Seibold, Götz A1 - Sigmund, Ernst A1 - Hizhnyakov, Vladimir T1 - Spin-Polaron Formation and Phase Separation Y1 - 1996 ER - TY - GEN A1 - Oelsen, E. von A1 - Seibold, Götz A1 - Bünemann, Jörg T1 - Time-Dependent Gutzwiller Theory for Multiband Hubbard Models T2 - Physical Review Letters Y1 - 2011 SN - 1079-7114 VL - 107 IS - 7 SP - 076402-01 EP - 076402-04 ER - TY - GEN A1 - Berger, Wolfram A1 - Hokamp, Sascha A1 - Seibold, Götz T1 - Dynamic behavioral changes in an agent-based econophysics tax compliance model. Bomb-crater versus target effects and efficient audit strategies T2 - Journal of Public Finance and Public Choice N2 - We investigate an inhomogeneous Ising model in the context of tax evasion dynamics where different types of agents are parametrised via local temperatures and magnetic fields. Our work focuses on the dynamic behavioural change of agents after an audit which either corresponds to a temporal reduction or enhancement of compliance and is also known under the terms 'bomb crater' and 'target effect', respectively. We analyse this effect for different types of agents: endogenously non-compliant types, agents that have the tendency to copy (non-)compliant behaviour from their social environment, ethical agents with strong endogenous morale attitudes and random types that show large uctuations between compliant and non-compliant behaviour. Each type in uences the overall tax evasion differently, and interestingly, our model predicts that increasing the audit probability can have the counterintuitive effect of increasing tax evasion under certain circumstances. We analyse audit strategies that can suppress this effect and thus contribute to the burgeoning literature on the actual impact of tax audits. Y1 - 2021 U6 - https://doi.org/10.1332/251569120X15840237292628 SN - 2515-6926 VL - 36 IS - 1 SP - 3 EP - 24 ER - TY - JOUR A1 - Seibold, Götz A1 - Sigmund, Ernst A1 - Hizhnyakov, Vladimir T1 - Unrestricted slave-boson mean-field approximation for the two-dimensional Hubbard model JF - Physical review Y1 - 1998 SN - 0556-2805 VL - 57 IS - 12 SP - 6937 EP - 6942 ER - TY - GEN A1 - Seibold, Götz T1 - Vortex, skyrmion and elliptical domain wall textures in thetwo-dimensional Hubbard model T2 - Physical review B Y1 - 1998 SN - 1550-235X VL - 58 IS - 23 SP - 15520 EP - 15527 ER - TY - JOUR A1 - Lorenzana, José A1 - Seibold, Götz T1 - Dynamics of metallic stripes in cuprates Y1 - 2003 ER - TY - GEN A1 - Udina, Mattia A1 - Fioro, Jacopo A1 - Cea, Tommaso A1 - Castellani, Claudio A1 - Seibold, Götz A1 - Benfatto, Lara T1 - THz non-linear optical response in cuprates: predominance of the BCS response over the Higgs mode T2 - Faraday Discussions N2 - Recent experiments with strong THz fields in unconventional cuprate superconductors have clearly evidenced an increase of the non-linear optical response below the superconducting critical temperature Tc. As in the case of conventional superconductors, a theoretical estimate of the various effects contributing to the non-linear response is needed in order to interpret the experimental findings. Here, we report a detailed quantitative analysis of the non-linear THz optical kernel in cuprates within a realistic model, accounting for the band structure and disorder level appropriate for these systems. We show that the BCS quasiparticle response is the dominant contribution for cuprates, and its polarization dependence accounts very well for the third-harmonic generation measurements. On the other hand, the polarization dependence of the THz Kerr effect is only partly captured by our calculations, suggesting the presence of additional effects when the system is probed using light pulses with different central frequencies. Y1 - 2022 UR - https://pubs.rsc.org/en/content/articlelanding/2022/FD/D2FD00016D U6 - https://doi.org/10.1039/D2FD00016D SN - 1364-5498 VL - 237 SP - 168 EP - 185 ER - TY - GEN A1 - Markiewicz, Richard S. A1 - Lorenzana, José A1 - Seibold, Götz A1 - Bansil, Arun T1 - Gutzwiller magnetic phase diagram of the cuprates Y1 - 2010 ER - TY - JOUR A1 - Lorenzana, José A1 - Seibold, Götz T1 - Dynamic properties of inhomogeneous states in cuprates Y1 - 2006 ER - TY - GEN A1 - Bünemann, Jörg A1 - Seibold, Götz T1 - Charge and pairing dynamics in the attractive Hubbard model: Mode coupling and the validity of linear-response theory T2 - Physical Review B N2 - 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. KW - Charge density waves KW - Hartree-Fock methods KW - Hubbard model KW - Linear response theory KW - Mean field theory KW - Variational wave functional methods Y1 - 2017 UR - https://journals.aps.org/prb/abstract/10.1103/PhysRevB.96.245139 U6 - https://doi.org/10.1103/PhysRevB.96.245139 SN - 2469-9977 SN - 1538-4489 VL - 96 IS - 24 ER - TY - GEN A1 - Miao, Hu A1 - Fumagalli, Roberto A1 - Rossi, M. A1 - Lorenzana, José A1 - Seibold, Götz A1 - Yakhou-Harris, Flora A1 - Kummer, K. A1 - Brookes, Nicholas B. A1 - Gu, G. D. A1 - Braicovich, Lucio A1 - Ghiringhelli, Giacomo Claudio A1 - Dean, M. P. M. T1 - Formation of Incommensurate Charge Density Waves in Cuprates T2 - Physical Review X N2 - 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. KW - Research Areas Charge density waves KW - Electrical Properties KW - Cuprates KW - Strongly correlated systems KW - Resonant inelastic x-ray scattering KW - Superconductivity Y1 - 2019 UR - https://journals.aps.org/prx/abstract/10.1103/PhysRevX.9.031042 U6 - https://doi.org/10.1103/PhysRevX.9.031042 SN - 2160-3308 VL - 9 IS - 3 SP - 031042-1 EP - 031042-11 ER - TY - GEN A1 - Martens, Christian A1 - Seibold, Götz T1 - Non-equilibrium dynamics of stripes in cuprate superconductors T2 - Journal of Magnetism and Magnetic Materials N2 - We use the time-dependent Gutzwiller approximation for the single-band Hubbard model to analyze the non-equilibrium dynamics for stripe ground states. In particular, we are interested in the interplay between spin and charge dynamics which is analyzed by quenching the system either in the charge or spin sector. This allows us to investigate the coupled relaxation dynamics as a function of the supplied energy. Further insight is provided by mapping the Gutzwiller dynamics onto a time-dependent Landau approach which lacks the double occupancy contribution to the time-evolution but allows to tune the coupling between spin- and charge degrees of freedom. KW - Hubbard model KW - Gutzwiller approximation KW - Landau KW - Non-equilibrium KW - Charge order KW - Spin order Y1 - 2022 UR - https://www.sciencedirect.com/science/article/pii/S030488532100812X U6 - https://doi.org/10.1016/j.jmmm.2021.168565 SN - 1873-4766 VL - 543 SP - 1 EP - 4 ER - TY - JOUR A1 - Seibold, Götz A1 - Lorenzana, José T1 - Gutzwiller+RPA Theory for Magnetic fluctuations from Stripes in Cuprates Y1 - 2007 ER - TY - JOUR A1 - Varlamov, Sergej A1 - Seibold, Götz T1 - Temperature dependence of the collective mode and its influence on theband splitting in bilayer cuprates Y1 - 2003 ER - TY - GEN A1 - Caprara, Sergio A1 - Di Castro, Carlo A1 - Seibold, Götz A1 - Grilli, Marco T1 - Dynamical charge density waves rule the phase diagram of cuprates T2 - Physical Review B N2 - 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. Y1 - 2017 UR - https://journals.aps.org/prb/abstract/10.1103/PhysRevB.95.224511 U6 - https://doi.org/https://doi.org/10.1103/PhysRevB.95.224511 SN - 2469-9950 SN - 2469-9969 VL - 95 IS - 22 SP - 224511 ER - TY - GEN A1 - Bovenzi, Nicandro A1 - Caprara, Sergio A1 - Grilli, Marco A1 - Raimondi, Roberto A1 - Scopigno, Niccolò A1 - Seibold, Götz T1 - Density inhomogeneities and Rashba spin-orbit coupling interplay in oxide interfaces T2 - Journal of Physics and Chemistry of Solids N2 - 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. Y1 - 2017 UR - https://www.sciencedirect.com/science/article/pii/S0022369717305991 SN - 0022-3697 ER - TY - JOUR A1 - Feinberg, D. A1 - Germain, P. A1 - Grilli, Marco A1 - Seibold, Götz T1 - Joint superexchange - Jahn-Teller mechanism for A-typeantiferromagnetism in LaMnO3 Y1 - 1998 ER - TY - CHAP A1 - Hizhnyakov, Vladimir A1 - Sigmund, Ernst A1 - Seibold, Götz T1 - Polaron Formation and Percolative Phase Separation T2 - Phase Separation in Cuprate Superconductors Y1 - 1994 SN - 3-540-57681-9 SP - 50 EP - 65 PB - Springer CY - Berlin [u.a.] ER - TY - JOUR A1 - Seibold, Götz T1 - Slave-boson based configuration-interaction approach for the Hubbard model JF - Physical Review B Y1 - 2008 SN - 1550-235X VL - 77 IS - 23 SP - 235109 ER - TY - JOUR A1 - Seibold, Götz T1 - Grundlagen und Anwendungen der Supraleitung JF - Unterrichtsblätter Deutsche Telekom Y1 - 2002 SN - 0949-3387 VL - 55 SP - S. 240 ER - TY - GEN A1 - Seibold, Götz A1 - Caprara, Sergio A1 - Grilli, Marco A1 - Raimondi, Roberto T1 - On the Evaluation of the Spin Galvanic Effect in Lattice Models with Rashba Spin-Orbit Coupling T2 - Condensed matter N2 - 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. KW - spintronics KW - spin-galvanic effect KW - lattice models Y1 - 2018 UR - http://www.mdpi.com/2410-3896/3/3/22 U6 - https://doi.org/10.3390/condmat3030022 SN - 2410-3896 VL - 3 IS - 33 SP - 1 EP - 10 ER - TY - CHAP A1 - Seibold, Götz A1 - Caprara, Sergio A1 - Raimondi, Roberto ED - Drouhin, Henri-Jean ED - Wegrowe, Jean-Eric ED - Razeghi, Manijeh ED - Jaffrès, Henri T1 - Theory of charge-spin conversion at oxide interfaces: the inverse spin-galvanic effect T2 - Spintronics XI, SPIE Nanoscience + Engineering, 19-23 August 2018, San Diego, California, United States N2 - 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. Y1 - 2018 UR - https://www.spiedigitallibrary.org/conference-proceedings-of-spie/10732/107322P/Theory-of-charge-spin-conversion-at-oxide-interfaces--the/10.1117/12.2319592.short U6 - https://doi.org/10.1117/12.2319592 PB - Spie CY - Bellingham, USA ER - TY - JOUR A1 - Seibold, Götz A1 - Grilli, Marco T1 - Theory of isotope dependence of photoemission spectra ofhigh-Tc superconducting cuprates Y1 - 2005 ER - TY - JOUR A1 - Seibold, Götz A1 - Grilli, Marco T1 - Influence of incommensurate dynamic charge-density wave scatteringon the line shape of superconducting high-Tc cuprates JF - Physical Review B Y1 - 2001 SN - 1550-235X VL - 63 IS - 22 SP - 224505 ER - TY - GEN A1 - Seibold, Götz A1 - Grilli, Marco A1 - Lorenzana, A. T1 - Dynamics of Electronic Inhomogeneities in Cuprates Y1 - 2011 ER -