Biaxial strain tuning of interlayer excitons in bilayer MoS2

TL;DR

This study demonstrates that biaxial strain significantly affects interlayer and intralayer excitonic features in bilayer MoS2, revealing strain-dependent gauge factors and the influence of van der Waals interactions.

Contribution

It provides the first quantitative analysis of how biaxial strain tunes interlayer excitons and gauge factors in bilayer MoS2, highlighting the role of van der Waals interactions.

Findings

Interlayer exciton shifts with larger gauge factor than A exciton.

Gauge factors for A and B excitons are -41 and -45 meV/% respectively.

Interlayer exciton gauge factor is -48 meV/%, larger due to strain-tunable van der Waals interaction.

Abstract

We show how the excitonic features of biaxial MoS2 flakes are very sensitive to biaxial strain. We find a lower bound for the gauge factors of the A exciton and B exciton of (-41 +- 2) meV/% and (-45 +- 2) meV/% respectively, which are larger than those found for single-layer MoS2. Interestingly, the interlayer exciton feature also shifts upon biaxial strain but with a gauge factor that is systematically larger than that found for the A exciton, (-48 +- 4) meV/%. We attribute this larger gauge factor for the interlayer exciton to the strain tunable van der Waals interaction due to the Poisson effect (the interlayer distance changes upon biaxial strain).