Theoretical 2D Raman band of strained graphene

TL;DR

This paper models the effects of uniaxial strain on the 2D Raman band of graphene, revealing band splitting and variations useful for strain detection in nanoelectronics.

Contribution

It provides a systematic theoretical analysis of 2D Raman band splitting in strained graphene using a non-orthogonal tight-binding model, including strain and laser energy dependence.

Findings

2D band splits into subbands under strain

Strain and dispersion rates vary up to 50%

Results aid in strain detection in graphene

Abstract

We study the 2D Raman band of in-plane uniaxially strained graphene within a non-orthogonal tight-binding model. At non-zero strain, the obtained 2D band splits into two subbands at strain angles $0^{\circ}$ and $30^{\circ}$ or into three subbands at intermediate angles. The evolution of the 2D subbands is calculated systematically in the range of the accessible strains from -1% to 3% and for the commonly used laser photon energy from 1.5 eV to 3.0 eV. The strain rate and dispersion rate of the 2D subbands are derived and tabulated. In particular, these two quantities show large variations up to 50%. The results on the 2D subbands can be used for detecting and monitoring strain in graphene for nanoelectronics applications.