Berry curvature in monolayer MoS$_2$ with broken mirror symmetry

TL;DR

This paper investigates how breaking mirror symmetry in monolayer MoS$_2$ affects its Berry curvature and related Hall effects, providing theoretical insights aligned with recent experimental observations.

Contribution

It introduces a theoretical analysis of mirror symmetry breaking effects on Berry curvature in monolayer MoS$_2$ using k·p perturbation theory, explaining experimental results.

Findings

Mirror symmetry breaking significantly alters Berry curvature.

Modified Berry curvature explains observed spin/valley Hall effects.

Results align qualitatively with recent experimental data.

Abstract

An ideal 1H phase monolayer MoS$_2$ has the mirror reflection symmetry but this symmetry is broken in common experimental situations, where the monolayer is placed on a substrate. By using the k$\cdot$p perturbation theory, we investigate the effect of the mirror symmetry breaking on the Berry curvature of the material. We find that the symmetry breaking may modify the Berry curvature considerably and the spin/valley Hall effect due to the modified Berry curvature is in qualitative agreement with a recent experimental result [Science $\bf 344$, 1489 (2014)], which cannot be explained by previous theories that ignore the mirror symmetry breaking.