Dynamical polarization of graphene under strain

TL;DR

This paper investigates how uniaxial strain affects the plasmon dispersion in graphene, revealing two plasmon branches and a nonmonotonic strain dependence of their properties, including local field effects and electron correlations.

Contribution

It introduces a detailed analysis of strain effects on graphene's plasmon dispersion, incorporating local field effects and revealing two distinct plasmon branches with nonmonotonic behavior.

Findings

Two plasmon branches identified in strained graphene.

Low-energy plasmon exhibits square-root dispersion.

Strain induces nonmonotonic changes in plasmon stiffness.

Abstract

We study the dependence of the plasmon dispersion relation of graphene on applied uniaxial strain. Besides electron correlation at the RPA level, we also include local field effects specific for the honeycomb lattice. As a consequence of the two-band character of the electronic band structure, we find two distinct plasmon branches. We recover the square-root behavior of the low-energy branch, and find a nonmonotonic dependence of the strain-induced modification of its stiffness, as a function of the wavevector orientation with respect to applied strain.