Abstract:

We study 2D electronic systems whose Fermi surfaces have type-II van Hove saddle points, defined as saddle points residing at time-reversal-noninvariant momenta in Brillouin zone. We propose that triplet pairing is generically favored in such 2D systems with weak repulsive interactions. This is argued quite generally from a renormalization group treatment of these systems. Such triplet pairing could give rise to topological superconductivity such as chiral p+ip superconductivity with robust chiral Majorana fermions in system boundaries and non-Abelian Majorana fermions in vortex cores. Possible applications to the Bi-based superconductor LaOBiS2 will also be discussed.
 
 
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