paper

Revisiting superconductivity in the extended one-band Hubbard model: pairing via spin and charge fluctuations

arXiv:2211.07423 · doi:10.1103/PhysRevB.106.214530

Abstract

The leading superconducting instabilities of the two-dimensional extended repulsive one-band Hubbard model within spin-fluctuation pairing theory depend sensitively on electron density, band and interaction parameters. We map out the phase diagrams within a random phase approximation (RPA) spin- and charge-fluctuation approach, and find that while () and () pairing dominates in the absence of repulsive longer-range Coulomb interactions , the latter induces pairing in other symmetry channels, including e.g (-wave), nodal (extended -wave), or nodal (-wave) spin-triplet superconductivity. At the lowest temperatures, transition boundaries in the phase diagrams between symmetry-distinct spin-singlet orders generate complex time-reversal symmetry broken superpositions. By contrast, we find that boundaries between singlet and triplet regions are characterized by first-order transitions. Finally, motivated by recent photoemission experiments, we have determined the influence of an additional explicitly attractive nearest-neighbor interaction, , on the superconducting gap structure. Depending on the electronic filling, such an attraction boosts (-wave) spin-triplet or () spin-singlet ordering.

12 pages, 6 figures

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