Platform for nodal topological superconductors in monolayer molybdenum dichalcogenides

TL;DR

This paper proposes a new platform using monolayer MoX2 materials to realize nodal topological superconductors with unique edge states, expanding possibilities for topological quantum devices.

Contribution

It introduces a method to achieve nodal topological superconductivity in monolayer MoX2 using in-plane magnetic fields, highlighting the emergence of protected zero-energy edge states.

Findings

Nodal points occur where spin splitting vanishes near K valleys.

Flat bands of zero-energy Andreev edge states connect nodal points.

Protected edge states are present for all boundary types except zigzag.

Abstract

We propose a platform to realize nodal topological superconductors in a superconducting monolayer of MoX$_2$ (X$=$S, Se, Te) using an in-plane magnetic field. The bulk nodal points appear where the spin splitting due to spin-orbit coupling vanishes near the $\pm \boldsymbol{K}$ valleys of the Brillouin zone, and are six or twelve per valley in total. In the nodal topological superconducting phase, the nodal points are connected by flat bands of zero-energy Andreev edge states. These flat bands, which are protected by chiral symmetry, are present for all lattice-termination boundaries except zigzag.