Strain induced bang-gap engineering in layered $\text{TiS}_3$

TL;DR

This study combines calculations and experiments to show how strain can tune the band gap of layered TiS3, enabling potential optical applications by controlling its electronic properties.

Contribution

It demonstrates strain-induced band gap modification in TiS3 through combined theoretical and experimental approaches, including a direct-to-indirect gap transition.

Findings

Band gap of TiS3 can be increased by up to 10% with tensile strain.

Strain induces a transition from direct to indirect band gap in monolayer and bilayer TiS3.

Optical absorption experiments confirm the theoretical predictions.

Abstract

By combining {\it ab initio} calculations and experiments we demonstrate how the band gap of the transition metal tri-chalcogenide TiS$_3$ can be modified by inducing tensile or compressive strain. We show by numerical calculations that the electronic band gap of layered TiS$_3$ can be modified for monolayer, bilayer and bulk material by inducing either hydrostatic pressure or strain. In addition, we find that the monolayer and bilayer exhibits a transition from a direct to indirect gap when the strain is increased in the direction of easy transport. The ability to control the band gap and its nature can have an impact in the use of TiS$_3$ for optical applications. We verify our prediction via optical absorption experiments that present a band gap increase of up to 10\% upon tensile stress application along the easy transport direction.