Majorana corner states in an attractive quantum spin Hall insulator with opposite in-plane Zeeman energy at two sublattice sites

TL;DR

This paper proposes a method to realize Majorana corner states in a 2D quantum spin-Hall insulator with opposite in-plane Zeeman energy at two sublattices, leading to a second-order topological superfluid.

Contribution

It introduces a novel scheme to engineer Majorana corner states using opposite Zeeman fields in an attractive quantum spin-Hall insulator, expanding possibilities for topological quantum states.

Findings

Majorana corner states can be realized with appropriate Zeeman fields.

The topological phase is characterized by Majorana edge polarizations.

The phase is robust against random potential perturbations.

Abstract

Higher-order topological superconductors and superfluids host lower-dimensional Majorana corner and hinge states since novel topology exhibitions on boundaries. While such topological nontrivial phases have been explored extensively, more possible schemes are necessary for engineering Majorana states. In this paper we propose Majorana corner states could be realized in a two-dimensional attractive quantum spin-Hall insulator with opposite in-plane Zeeman energy at two sublattice sites. The appropriate Zeeman field leads to the opposite Dirac mass for adjacent edges of a square sample, and naturally induce Majorana corner states. This topological phase can be characterized by Majorana edge polarizations, and it is robust against perturbations on random potentials as long as the edge gap remains open. Our work provides a new possibility to realize a second-order topological superfluid in two dimensions and engineer Majorana corner states.