Symmetry-based approach to electron-phonon interactions in graphene

TL;DR

This paper employs symmetry principles to derive general, model-independent constraints on electron-phonon interactions in graphene, providing a comprehensive framework for understanding electron-phonon coupling and strain effects.

Contribution

It introduces a symmetry-based method to determine the most general electron-phonon couplings in graphene, independent of specific models.

Findings

Derived symmetry constraints on electron-phonon Hamiltonian

Provided explicit series expansion for couplings

Analyzed strain effects as effective electromagnetic fields

Abstract

We use the symmetries of monolayer graphene to write a set of constraints that must be satisfied by any electron-phonon interaction hamiltonian. The explicit solution as a series expansion in the momenta gives the most general, model-independent couplings between electrons and long wavelength acoustic and optical phonons. As an application, the possibility of describing elastic strains in terms of effective electromagnetic fields is considered in detail, with an emphasis on group theory conditions and the role of time reversal symmetry.