Strain induced band gap deformation of H/F passivated graphene and h-BN sheet

TL;DR

This study uses first principles calculations to analyze how strain affects the band gap of passivated graphene and BN sheets, revealing differences from pristine materials and estimating their mechanical strength.

Contribution

It provides the first detailed analysis of strain-induced band gap deformation in passivated graphene and BN sheets using density functional theory.

Findings

Hydrogenated systems show higher band gap deformation than fluorinated ones.

Passivated systems exhibit positive band gap deformation, unlike pristine sheets.

Fluorinated and hydrogenated graphene have higher in-plane stiffness than their BN counterparts.

Abstract

Strain induced band gap deformations of hydrogenated/fluorinated graphene and hexagonal BN sheet have been investigated using first principles density functional calculations. Within harmonic approximation, the deformation is found to be higher for hydrogenated systems than for the fluorinated systems. Interestingly, our calculated band gap deformation for hydrogenated/fluorinated graphene and BN sheets are positive, while those for pristine graphene and BN sheet are found to be negative. This is due to the strong overlap between nearest neighbor {\pi} orbitals in the pristine sheets, that is absent in the passivated systems. We also estimate the intrinsic strength of these materials under harmonic uniaxial strain, and find that the in-plane stiffness of fluorinated and hydrogenated graphene are close, but larger in magnitude as compared to those of fluorinated and hydrogenated BN sheet.