Impact of strain on the excitonic linewidth in transition metal dichalcogenides

TL;DR

This paper investigates how tensile and compressive strain affect the excitonic linewidths in monolayer transition metal dichalcogenides, providing microscopic insights and predicting their optical response under different strain conditions.

Contribution

It offers a detailed microscopic analysis of strain effects on excitonic linewidths in TMDs, combining first-principles calculations with experimental explanations.

Findings

Strain modifies electron and phonon dispersion in TMDs.

Excitonic linewidths change predictably under tensile and compressive strain.

Theoretical predictions align with recent experimental observations.

Abstract

Monolayer transition metal dichalcogenides (TMDs) are known to be highly sensitive to externally applied tensile or compressive strain. In particular, strain can be exploited as a tool to control the optical response of TMDs. However, the role of excitonic effects under strain has not been fully understood yet. Utilizing the strain-induced modification of electron and phonon dispersion obtained by first principle calculations, we present in this work microscopic insights into the strain-dependent optical response of various TMD materials. In particular, we explain recent experiments on the change of excitonic linewidths in strained TMDs and predict their behavior for tensile and compressive strain at low temperatures.