Exotic Cooper pairing in multiorbital models of Sr2RuO4

Article

关键词: SPIN-TRIPLET SUPERCONDUCTIVITY;    FERMI-SURFACE;   

DOI  :  10.1103/PhysRevB.100.134506

来源: SCIE

【 摘 要 】

The unconventional superconductivity in Sr2RuO4 continues to defy a unified interpretation. In this paper, we focus on some novel aspects of its superconducting pairing by exploiting the orbital degree of freedom in this material. The multiorbital nature, combined with the symmetry of the orbitals involved, leads to a plethora of exotic Cooper pairings not accessible in single-orbital systems. Essential physics is illustrated first using a two-orbital model with d(xz) and d(yz) orbitals. We classify the gap functions according to the underlying lattice symmetries, analyze the effective theories of a few representative pairings, and make connections to Sr2RuO4 in the course. In particular, we show how spin-orbit coupling may entangle spin-triplet and spin-singlet pairings. For completeness, the classification is generalized to the three-orbital model involving the d(xy) orbital as well. The orbital-basis approach distinguishes from the itinerant-band description for Sr2RuO4 and hence offers an alternative perspective to investigate its enigmatic superconducting state.

【 授权许可】

Free