TY - JOUR A1 - Seibold, Götz A1 - Lorenzana, José T1 - Time-dependent Gutzwiller approximation for the Hubbard Model Y1 - 2001 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 - Lorenzana, José T1 - The unrestricted Gutzwiller+RPA approach and its application to stripes in cuprates Y1 - 2005 ER - TY - JOUR A1 - Guenther, Falk A1 - Seibold, Götz A1 - Lorenzana, José T1 - Quantum Lifshitz point in the infinite dimensional Hubbard model Y1 - 2007 ER - TY - JOUR A1 - Seibold, Götz A1 - Becca, Federico A1 - Lorenzana, José T1 - Time dependent Gutzwiller theory of pairing fluctuations in the Hubbard model JF - Physical Review B KW - Correlated electrons KW - Hubbard mode KW - Pairing correlations Y1 - 2008 SN - 0556-2805 VL - 78 SP - 045114 ER - TY - GEN A1 - Di Ciolo, A. A1 - Lorenzana, José A1 - Grilli, Marco A1 - Seibold, Götz T1 - Charge instabilities and electron-phonon interaction in the Hubbard-Holstein model T2 - Physical Review B KW - strongly correlated systems Y1 - 2009 SN - 1550-235X VL - 79 SP - 085101 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 - 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 - 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 - 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 - 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 - Oelsen, E. von A1 - Di Ciolo, A. A1 - Lorenzana, José A1 - Seibold, Götz A1 - Grilli, Marco T1 - Phonon renormalization from local and transitive electron-latticecouplings in strongly correlated systems Y1 - 2010 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 - Markiewicz, Richard S. A1 - Lorenzana, José A1 - Seibold, Götz A1 - Bansil, Arun T1 - Gutzwiller magnetic phase diagram of the cuprates Y1 - 2010 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 - 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 - JOUR A1 - Lorenzana, José A1 - Seibold, Götz A1 - Ortix, C. A1 - Grilli, Marco T1 - Competing orders in FeAs layers Y1 - 2008 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 - 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 - JOUR A1 - Seibold, Götz A1 - Lorenzana, José T1 - Gutzwiller+RPA Theory for Magnetic fluctuations from Stripes in Cuprates Y1 - 2007 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 - Unified description of charge and spin excitations of stripes in cuprates Y1 - 2007 ER - TY - JOUR A1 - Di Ciolo, A. A1 - Lorenzana, José A1 - Seibold, Götz A1 - Grilli, Marco T1 - Paramagnetic stripes in cuprates: charge inhomogeneity coexisting with large Fermi surfaces 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 - JOUR A1 - Lorenzana, José A1 - Seibold, Götz T1 - Dynamic properties of inhomogeneous states in cuprates Y1 - 2006 ER - TY - JOUR A1 - Lorenzana, José A1 - Seibold, Götz T1 - Metallic mean-field stripes, incommensurability and chemicalpotential in cuprates Y1 - 2002 ER - TY - JOUR A1 - Seibold, Götz A1 - Lorenzana, José T1 - Magnetic fluctuations of stripes in the high temperature cuprate superconductors Y1 - 2005 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 - 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 - JOUR A1 - Lorenzana, José A1 - Seibold, Götz T1 - Dynamical and statical properties of stripes in cuprates Y1 - 2004 ER - TY - JOUR A1 - Lorenzana, José A1 - Seibold, Götz T1 - Dynamics of metallic stripes in cuprates Y1 - 2003 ER - TY - JOUR A1 - Seibold, Götz A1 - Becca, Federico A1 - Lorenzana, José T1 - Inhomogeneous Gutzwiller approximation with random phase fluctuationsfor the Hubbard model Y1 - 2003 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 - 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 - Seibold, Götz A1 - Grilli, Marco A1 - Lorenzana, José T1 - Influence of correlations on transitive electron-phonon couplings in cuprate superconductors Y1 - 2011 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 - 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 - 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 - 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 - 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 - 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 - Lemarié, Gabriel A1 - Kamlapure, Anand A1 - Benfatto, Lara A1 - Lorenzana, José A1 - Seibold, Götz A1 - Ganguli, S. C. A1 - Raychaudhuri, Pratap A1 - Castellani, Claudio T1 - Universal scaling of the order-parameter distribution in strongly disordered superconductors T2 - Physical Review B N2 - We investigate theoretically and experimentally the statistical properties of the inhomogeneous order-parameter distribution (OPD) at the verge of the superconductor-insulator transition (SIT). We find within two prototype fermionic and bosonic models for disordered superconductors that one can identify a universal rescaling of the OPD. By performing scanning-tunneling microscopy experiments in three samples of NbN with increasing disorder we show that such a rescaling also describes the experimental data with excellent accuracy. These results can provide a breakthrough in our understanding of the SIT. Y1 - 2013 UR - http://journals.aps.org/prb/abstract/10.1103/PhysRevB.87.184509 U6 - https://doi.org/10.1103/PhysRevB.87.184509 SN - 2469-9977 VL - 87 IS - 18 SP - 184509 ER - TY - GEN A1 - Seibold, Götz A1 - Capati, Matteo A1 - Grilli, Marco A1 - Di Castro, Carlo A1 - Grilli, Marco A1 - Lorenzana, José T1 - Hidden ferronematic order in underdoped cuprates T2 - Physical Review B N2 - We study a model for low-doped cuprates where holes aggregate into oriented stripe segments which have a magnetic vortex and antivortex at the extremes. We argue that due to the interaction between segments a ferronematic state with macroscopic polarization is stabilized. This state can be characterized as a charge nematic which, due to the net polarization, breaks inversion symmetry and also exhibits an incommensurate spin modulation. Our calculation can reproduce the doping-dependent spin structure factor of lanthanum cuprates in excellent agreement with experiment and allows to rationalize experiments in which the incommensurability has an order-parameter-like temperature dependence. Y1 - 2013 UR - http://journals.aps.org/prb/abstract/10.1103/PhysRevB.87.035138 U6 - https://doi.org/10.1103/PhysRevB.87.035138 SN - 2469-9969 VL - 87 IS - 3 SP - 035138 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - Seibold, Götz A1 - Lorenzana, Jose T1 - Nonequilibrium dynamics from BCS to the bosonic limit T2 - Physical Review B N2 - Within the time-dependent Gutzwiller approximation applied to the negative-U Hubbard model, we investigate the dynamics of a superconductor after an interaction quench for different values of the final interaction from weak to strong coupling. The equilibrium BCS-BEC crossover becomes a sharp transition in the out-of-equilibrium dynamics between weak- and strong-coupling dynamical phases. Two different frequencies (ΩJ<ΩU) dominate the order parameter dynamics. In the weak coupling phase, ΩJ follows twice the asymptotic average value of the gap (ΩJ≈2Δ∞) and ΩU is much larger but hardy visible in the anomalous density. At long times the BCS dynamics is recovered but surprisingly differences remain during the transient phase. In the strong coupling phase, the dynamics decouples from the asymptotic value of the order parameter except at exactly half filling and close to the dynamical transition where ΩU≈2Δ∞. The out-of-equilibrium transient spectral density and optical conductivity are presented and discussed in relation to pump probe experiments. Both ΩJ and ΩU give rise to a complex structure of self-driven slow Rabi oscillations which are visible in the nonequilibrium optical conductivity where also sidebands appear due to the modulation of the double occupancy by superconducting amplitude oscillations. Analogous results apply to CDW and SDW systems. Our results show that in systems with long coherence times, pump-probe experiments allow us to characterize the regime (BCS vs preformed pairs) through very specific out-of-equilibrium fingerprints. KW - BEC-BCS crossover KW - Superconductivity fluctuations KW - Superconductivity Y1 - 2020 UR - https://journals.aps.org/prb/abstract/10.1103/PhysRevB.102.144502 U6 - https://doi.org/10.1103/PhysRevB.102.144502 SN - 2469-9969 VL - 102 IS - 14 ER - TY - GEN A1 - Seibold, Götz A1 - Castellani, Claudio A1 - Lorenzana, José T1 - Adiabatic transition from a BCS superconductor to a Fermi liquid and phase dynamics T2 - Physical Review B N2 - We investigate the physics of an adiabatic transition from a BCS superconductor to a Fermi liquid for an exponentially slow decreasing pairing interaction. We show that, depending on the order of the thermodynamic limit and large times, a situation can arise in which the Fermi liquid keeps a memory of the parent BCS state. Furthermore, a time inversion of the interaction, supplemented by a manipulation analogous to a spin-/photon-echo experiment, allows us to recover the parent BCS state. Moreover, we study the evolution of the order parameter phase ϕ in transforming the BCS superconductor to a conventional metal. Since the global phase is the conjugate variable of the density, we explicitly show how to use the dynamics of ϕ together with gauge invariance to build up the noninteracting chemical potential away from particle-hole symmetry. We further analyze the role of ϕ in restoring the gauge-invariant current response when the noninteracting Fermi liquid is approached starting from a BCS superconductor in the presence of an external vector field. KW - Superconductivity KW - Nonequilibrium systems KW - Adiabatic approximation KW - BCS theory KW - Gauge symmetries KW - Variational approach Y1 - 2022 UR - https://journals.aps.org/prb/abstract/10.1103/PhysRevB.105.184513 U6 - https://doi.org/10.1103/PhysRevB.105.184513 SN - 2469-9969 VL - 105 IS - 18 SP - 184513-1 EP - 184513-14 ER - TY - GEN A1 - Lorenzana, José A1 - Seibold, Götz T1 - Undamped higgs modes in strongly interacting superconductors T2 - Condens Matter N2 - In superconductors, gauge 𝑈(1) symmetry is spontaneously broken. According to Goldstone’s theorem, this breaking of a continuous symmetry establishes the existence of the Bogoliubov phase mode while the gauge-invariant response also includes the amplitude fluctuations of the order parameter. The latter, which are also termed ‘Higgs’ modes in analogy with the standard model, appear at the energy of the spectral gap 2Δ, when the superconducting ground state is evaluated within the weak-coupling BCS theory, and, therefore, are damped. Previously, we have shown that, within the time-dependent Gutzwiller approximation (TDGA), Higgs modes appear inside the gap with a finite binding energy relative to the quasiparticle continuum. Here, we show that the binding energy of the Higgs mode becomes exponentially small in the weak-coupling limit converging to the BCS solution. On the other hand, well-defined undamped amplitude modes exist in strongly coupled superconductors when the interaction energy becomes of the order of the bandwidth. KW - superconductivity KW - time-dependent Gutzwiller KW - collective modes Y1 - 2024 U6 - https://doi.org/10.3390/condmat9040038 VL - 9 IS - 4 SP - 1 EP - 12 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 -