Inter-orbital singlet pairing in Sr$_2$RuO$_4$: a Hund's superconductor
Abstract
We study the superconducting gap function of SrRuO. By solving the linearized Eliashberg equation with a correlated pairing vertex extracted from a dynamical mean-field calculation we identify the dominant pairing channels. An analysis of the candidate gap functions in orbital and quasiparticle band basis reveals that an inter-orbital singlet pairing of even parity is in agreement with experimental observations. It reconciles in particular the occurrence of a two-component order parameter with the presence of line-nodes of quasiparticles along the c-axis in the superconducting phase. The strong angular dependence of the gap along the Fermi surface is in stark contrast to its quasi-locality when expressed in the orbital basis. We identify local inter-orbital spin correlations as the driving force for the pairing and thus reveal the continuation of Hund's physics into the superconducting phase.
Keywords
Cite
@article{arxiv.2105.08448,
title = {Inter-orbital singlet pairing in Sr$_2$RuO$_4$: a Hund's superconductor},
author = {Stefan Käser and Hugo U. R. Strand and Nils Wentzell and Antoine Georges and Olivier Parcollet and Philipp Hansmann},
journal= {arXiv preprint arXiv:2105.08448},
year = {2022}
}
Comments
20 pages, 12 figures