Effects of orbital selective dynamical correlation on the spin susceptibility and superconducting symmetries in Sr2RuO4

Abstract

We investigate the connection between the local electron correlation and the momentum dependence of the spin susceptibility and the superconducting gap functions in Sr2RuO4 using density-functional theory combined with dynamical mean-field theory. Adopting a frequency-dependent two-particle vertex moves the zero-energy spin susceptibility peaks towards the Brillouin zone center, compared with the random-phase approximation, which basically retains the peak positions closer to the Brillouin zone boundary as determined by the Fermi-surface nesting. We find that the dxy orbital plays a central role here via its enhanced correlation strength. Solving the linearized Eliashberg equation from this spin susceptibility, the prime candidates for the superconducting gap are an s-wave and a nearly degenerate d-wave solutions, all in the spin singlet. Furthermore, another set of degenerate spin-singlet gap functions emerges, odd with respect to the k point as well as orbital exchanges. We show that the stability of these gap functions is strongly dependent on the peak position of the spin susceptibility in the Brillouin zone.

Source-reported materials — not catalogue approval

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