A simple Tight-Binding Approach to Topological Superconductivity in Monolayer MoS2

TL;DR

This paper presents a simple tight-binding model for monolayer MoS2, revealing conditions for topological superconductivity with Majorana states and demonstrating phase stability under uniaxial strain.

Contribution

It introduces a straightforward tight-binding Hamiltonian for MoS2 to study topological superconductivity and characterizes the phase diagram including Majorana states and strain effects.

Findings

Spin-singlet p+ip wave phase is topological with nonzero Chern numbers.

Majorana zero modes exist under certain chemical potential and SOC conditions.

Topological phase remains stable under uniaxial strain.

Abstract

Monolayer molybdenum disulfide (MoS2) has a honeycomb crystal structure. We consider the triangular sublattice of molybdenum atoms and introduce a simple tight-binding Hamiltonian for studying the phase transition and topological superconductivity in MoS2 under uniaxial strain. It is shown that spin-singlet p+ip wave phase is a topological superconducting phase which possesses nonzero Chern numbers. When the chemical potential is bigger (smaller) than the spin-orbit coupling (SOC) strength the Chern number is equal to four (two) and otherwise it is equal to zero. Also, it is shown that, when the superconductivity gap is smaller and the chemical potential is bigger than the SOC strength, the zero energy Majorana states exist. Finally, we show the topological superconducting phase is preserved under uniaxial strain.