External-strain-induced semimetallic and metallic phase of chlorographene

TL;DR

This study uses ab initio calculations to show how external strain can induce semimetallic and metallic phases in chlorographene, revealing strain-dependent electronic transitions and the role of spin-orbit coupling in gap formation.

Contribution

It demonstrates strain-induced electronic phase transitions in chlorographene and highlights the significance of spin-orbit coupling in its band gap behavior.

Findings

Tensile strain reduces chlorographene's band gap to near zero.

Compressive strain can turn chlorographene into a metal.

Spin-orbit coupling causes a small band gap under high tensile strain.

Abstract

To overcome the limitations of graphene due to lack of intrinsic band gap, it is generally functionalized with hydrogen or halogen atoms such as fluorine and chlorine. Generally, such functionalization yields a moderate- to high-band-gap material in case of 100% coverage, for example ~1.5 eV in graphene functionalized with chlorine atoms or chlorographene. In this paper, using ab initio calculations, we report very interesting transformations observed in chlorographene under external strain, driving it to a state with nearly vanishing band gap (under tensile strain) and even converting it to a metal (under compressive strain). We also show the importance of spin-orbit coupling, responsible for the few meV band gap of chlorographene observed under high tensile strain, which would have been a gapless semimetal otherwise.