Topological odd-parity superconductivity at type-II two-dimensional van Hove singularities

Hong Yao; Fan Yang

doi:10.1103/PhysRevB.92.035132

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Topological odd-parity superconductivity at type-II two-dimensional van Hove singularities

Hong Yao, Fan Yang

DOI 10.1103/PhysRevB.92.035132 · Physical Review B

T1

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Abstract

We study unconventional superconductivity induced by weak repulsive interactions in 2D electronic systems at van Hove singularity (VHS) where density of states is logarithmically divergent. We define two types of VHS. For systems at type-I VHS, weak repulsive interactions generically induce unconventional singlet pairing. However, and more interestingly, for type-II VHS renormalization group analysis shows that weak repulsive interactions favor triplet pairing (e.g., p wave) when the Fermi surface is not sufficiently nested. For type-II VHS systems respecting tetragonal symmetry, topological superconductivity (either chiral p+ip pairing or time-reversal invariant Z2p+ip pairing) occurs generally. We shall also discuss relevance of our study to materials including recently discovered superconductors LaO1−xFxBiS2, which can be tuned to type-II VHS by doping.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
LaO1-xFxBiS2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown
Sr2RuO4 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown