A tight-binding approach to uniaxial strain in graphene

TL;DR

This paper investigates how uniaxial strain affects graphene's electronic properties, revealing that significant strain can open a spectral gap, but only beyond a critical threshold and along specific directions, with implications for device transport.

Contribution

It provides a detailed analysis of strain-induced spectral gap formation in graphene using a tight-binding model within linear elasticity theory, highlighting the conditions for gap emergence.

Findings

Strain can generate a bulk spectral gap in graphene.

A critical deformation threshold of over 20% is needed for gap opening.

The gapless Dirac spectrum remains robust under small to moderate strains.

Abstract

We analyze the effect of tensional strain in the electronic structure of graphene. In the absence of electron-electron interactions, within linear elasticity theory, and a tight-binding approach, we observe that strain can generate a bulk spectral gap. However this gap is critical, requiring threshold deformations in excess of 20%, and only along preferred directions with respect to the underlying lattice. The gapless Dirac spectrum is robust for small and moderate deformations, and the gap appears as a consequence of the merging of the two inequivalent Dirac points, only under considerable deformations of the lattice. We discuss how strain-induced anisotropy and local deformations can be used as a means to affect transport characteristics and pinch off current flow in graphene devices.