Surface density of states and topological edge states in non-centrosymmetric superconductors

TL;DR

This paper investigates the surface states and topological properties of non-centrosymmetric superconductors with mixed pairing symmetries, revealing Majorana edge modes and their dependence on magnetic fields.

Contribution

It demonstrates the existence of Majorana edge modes in non-centrosymmetric superconductors with mixed pairing, and analyzes their topological invariants and surface density of states.

Findings

Zero energy Andreev bound states as Majorana modes

Surface density of states depends on Zeeman field direction

Topological invariant confirms Majorana edge mode presence

Abstract

We study Andreev bound state (ABS) and surface density of state (SDOS) of non-centrosymmetric superconductor where spin-singlet $d$-wave pairing mixes with spin-triplet $p$ (or $f)$-wave one by spin-orbit coupling. For $d_{xy} + p$-wave pairing, ABS appears as a zero energy state. The present ABS is a Majorana edge mode preserving the time reversal symmetry. We calculate topological invariant number and discuss the relevance to a single Majorana edge mode. In the presence of the Majorana edge mode, the SDOS depends strongly on the direction of the Zeeman field.