Pairing symmetry of the one-band Hubbard model in the paramagnetic weak-coupling limit: A numerical RPA study

Rømer, Astrid T.; Kreisel, Andreas; Eremin, I.; Malakhov, M. A.; Maier, Thomas; Hirschfeld, P. J.; Andersen, Brian M.

doi:10.1103/physrevb.92.104505

Cited by 64 publications

(59 citation statements)

References 39 publications

(78 reference statements)

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“…Several authors, including the current ones, have applied various weak-coupling schemes to map out the leading superconducting instabilities as a function of e.g. doping and band parameters, displaying a rich mosaic of different pairing states [36][37][38][39][40][41][42]. Predictions of these studies for leading pairing instabilities throughout the phase diagram appear to agree rather well with recent diagrammatic Monte Carlo calculations that should be well-controlled and able to reach somewhat higher U [24].…”

Section: Introductionsupporting

confidence: 56%

“…In contrast to DCA, however, in the low-U limit, the triplet solution denoted p becomes the second leading instability. This is due to the proximity to the van Hove singularity, which is known to enhance the effective triplet pairing interaction [39]. For t = −0.15 the critical density for which the van Hove saddle points reside at the Fermi surface is n van Hove = 0.875 and at n = 0.90 we are thus not far from this regime.…”

Section: Resultsmentioning

confidence: 85%

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Pairing in the two-dimensional Hubbard model from weak to strong coupling

Rømer

Maier

Kreisel

et al. 2020

Phys. Rev. Research

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The Hubbard model is the simplest model that is believed to exhibit superconductivity arising from purely repulsive interactions, and has been extensively applied to explore a variety of unconventional superconducting systems. Here we study the evolution of the leading superconducting instabilities of the single-orbital Hubbard model on a two-dimensional square lattice as a function of onsite Coulomb repulsion U and band filling by calculating the irreducible particle-particle scattering vertex obtained from dynamical cluster approximation (DCA) calculations, and compare the results to both perturbative Kohn-Luttinger (KL) theory as well as the widely used random phase approximation (RPA) spin-fluctuation pairing scheme. Near half-filling we find remarkable agreement of the hierarchy of the leading pairing states between these three methods, implying adiabatic continuity between weak-and strong-coupling pairing solutions of the Hubbard model. The d x 2 −y 2 -wave instability is robust to increasing U near half-filling as expected. Away from half filling, the predictions of KL and RPA at small U for transitions to other pair states agree with DCA at intermediate U as well as recent diagrammatic Monte Carlo calculations. RPA results fail only in the very dilute limit, where it yields a dxy ground state instead of a p-wave state established by diagrammatic Monte Carlo and low-order perturbative methods, as well as our DCA calculations. We discuss the origins of this discrepancy, highlighting the crucial role of the vertex corrections neglected in the RPA approach. Overall, comparison of the various methods over the entire phase diagram strongly suggests a smooth crossover of the superconducting interaction generated by local Hubbard interactions between weak and strong coupling.I.

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Section: Introductionsupporting

confidence: 56%

Section: Resultsmentioning

confidence: 85%

Pairing in the two-dimensional Hubbard model from weak to strong coupling

Rømer

Maier

Kreisel

et al. 2020

Phys. Rev. Research

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“…This approach modifies the pairing interaction in orbital space and thus also in-fluences the superconducting gap found when solving the linearized gap equation [104,124] or the Bogoliubov de Gennes equation self-consistently [119,120].…”

Section: Gap Magnitude and Orbital Content Of The Fermi Surfacementioning

confidence: 99%

“…The superconducting gap is taken from a self-consistent calculation, [119,120] using the same band structure and pairing model as outlined in chapters 3 and 7.…”

Section: Sign-changing or Sign-preserving Superconductivity?mentioning

confidence: 99%

Discovery of orbital-selective Cooper pairing in FeSe

Sprau

Kostin

Kreisel

et al. 2017

Science

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368

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FeSe is the focus of intense research interest because of its unusual non-magnetic nematic state and because it forms the basis for achieving the highest critical temperatures of any iron-based superconductor. However, its Cooper pairing mechanism has not been determined because an accurate knowledge of the momentum-space structure of superconducting energy gaps ∆ i ( k) on the different electron-bands E i ( k) does not exist. Here we use Bogoliubov quasiparticle interference (BQPI) imaging to determine the coherent Fermi surface geometry of the α-and ε-bands surrounding the Γ = (0, 0) and X = (π/a Fe , 0) points of FeSe, and to measure their superconducting energy gaps ∆ α ( k) and ∆ ε ( k).We show directly that both gaps are extremely anisotropic but nodeless, and are aligned along orthogonal crystal axes. Moreover, by implementing a novel technique we demonstrate the sign change between ∆ α ( k) and ∆ ε ( k). This complex configuration of ∆ α ( k) and ∆ ε ( k), which was unanticipated within pairing theories for FeSe, reveals a unique form of superconductivity based on orbital selective Cooper pairing of electrons from the d yz orbitals of iron atoms. This new paradigm of orbital selectivity may be pivotal to understanding the microscopic interplay of quantum paramagnetism, nematicity and high temperature superconductivity. BIOGRAPHICAL SKETCHPeter Oliver Sprau was born on June 13th 1986 in the small town of Kirchheimbolanden, Germany, where he completed both his primary and secondary education. Long before he was a physicist, Peter was an active member of the track and field team in his school and a local club, even going on to compete in the dash and relay event on the state and federal youth level. Upon finishing school, he fulfilled his civic duty and carried out his alternative civilian service in the hospital in Kirchheimbolanden. While Peter's academic interests were diverse, including not just science but also Latin and history, his natural curiosity about the world finally urged him to pursue a higher education in physics. Mistakes. Make glorious, amazing mistakes. Make mistakes nobody's ever made before. Don't freeze, don't stop, don't worry that it isn't good enough, or it isn't perfect, whatever it is: art, or love, or work or family or life.Whatever it is you're scared of doing, Do it. Make your mistakes, next year and forever." I also want to acknowledge in no specific order the following people for useful discussions throughout my PhD:

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“…The pairing interactions Γ µ µνν (k, k ) are derived from standard spin-fluctuation theory 23 together with a proper symmetrization in the spin-singlet channel 24 as outlined in Appendix B 1. For a visualization of the superconducting gap in band space, the normal-state transformation that diagonalizesĤ(k) of Eq.…”

Section: B Superconducting Gapmentioning

confidence: 99%

Towards a quantitative description of tunneling conductance of superconductors: Application to LiFeAs

et al. 2016

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Since the discovery of iron-based superconductors, a number of theories have been put forward to explain the qualitative origin of pairing, but there have been few attempts to make quantitative, material-specific comparisons to experimental results. The spin-fluctuation theory of electronic pairing, based on first-principles electronic structure calculations, makes predictions for the superconducting gap. Within the same framework, the surface wave functions may also be calculated, allowing, e.g., for detailed comparisons between theoretical results and measured scanning tunneling topographs and spectra. Here we present such a comparison between theory and experiment on the Fe-based superconductor LiFeAs. Results for the homogeneous surface as well as impurity states are presented as a benchmark test of the theory. For the homogeneous system, we argue that the maxima of topographic image intensity may be located at positions above either the As or Li atoms, depending on tip height and the setpoint current of the measurement. We further report the experimental observation of transitions between As and Li-registered lattices as functions of both tip height and setpoint bias, in agreement with this prediction. Next, we give a detailed comparison between the simulated scanning tunneling microscopy images of transition-metal defects with experiment. Finally, we discuss possible extensions of the current framework to obtain a theory with true predictive power for scanning tunneling microscopy in Fe-based systems.

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Pairing symmetry of the one-band Hubbard model in the paramagnetic weak-coupling limit: A numerical RPA study

Cited by 64 publications

References 39 publications

Pairing in the two-dimensional Hubbard model from weak to strong coupling

Pairing in the two-dimensional Hubbard model from weak to strong coupling

Discovery of orbital-selective Cooper pairing in FeSe

Towards a quantitative description of tunneling conductance of superconductors: Application to LiFeAs

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