Effect of electron-electron interaction on the Fermi surface topology of doped graphene

TL;DR

This paper investigates how electron-electron interactions influence the Fermi surface topology of doped graphene, considering lattice effects and Coulomb interactions, revealing preservation of trigonal warping and anisotropic deformations.

Contribution

It provides a detailed analysis of electron-electron interaction effects on doped graphene's Fermi surface, incorporating lattice discreteness and Coulomb interactions with self-energy calculations.

Findings

Trigonal warping preserved by exchange self-energy corrections

Band velocity renormalized to higher values

Local Coulomb interactions cause anisotropic Fermi surface deformation

Abstract

The electron-electron interactions effects on the shape of the Fermi surface of doped graphene are investigated. The actual discrete nature of the lattice is fully taken into account. A $\pi$-band tight-binding model, with nearest-neighbor hopping integrals, is considered. We calculate the self-energy corrections at zero temperature. Long and short range Coulomb interactions are included. The exchange self-energy corrections for graphene preserve the trigonal warping of the Fermi surface topology, although rounding the triangular shape. The band velocity is renormalized to higher value. Corrections induced by a local Coulomb interaction, calculated by second order perturbation theory, do deform anisotropically the Fermi surface shape. Results are compared to experimental observations and to other theoretical results.