The two-dimensional Brillouin zone of uniaxially strained graphene

TL;DR

This paper uses ab-initio calculations to analyze how uniaxial strain affects the electronic and vibrational properties of graphene, revealing strain-dependent shifts in Raman modes that enable strain measurement.

Contribution

It provides a detailed analysis of strain effects on graphene's band structure and Raman spectra, highlighting strain-independent frequency shifts useful for sensing.

Findings

Fermi crossing shifts away from K-point with strain

Graphene remains semimetallic under small strains

Strain-induced Raman shifts are independent of strain direction

Abstract

We present an in-depth analysis of the electronic and vibrational band structure of uniaxially strained graphene by ab-initio calculations. Depending on the direction and amount of strain, the Fermi crossing moves away from the $K$-point. However, graphene remains semimetallic under small strains. The deformation of the Dirac cone near the $K$-point gives rise to a broadening of the 2D Raman mode. In spite of specific changes in the electronic and vibrational band structure the strain-induced frequency shifts of the Raman active E2g and 2D modes are independent of the direction of strain. Thus, the amount of strain can be directly determined from a single Raman measurement.