Deformation of anisotropic Fermi surfaces due to electron-electron interactions

TL;DR

This paper investigates how electron-electron interactions cause deformations in anisotropic Fermi surfaces in two-dimensional systems, revealing complex momentum-dependent behaviors even at weak coupling.

Contribution

It introduces a perturbative analytical approach that accounts for both regular and singular Fermi surface regions to describe deformations due to interactions.

Findings

Self-energy exhibits nontrivial momentum dependence.

Deformations occur even at weak local coupling.

Analytical expressions relate Fermi surface features to interaction effects.

Abstract

We analyze the deformations of the Fermi surface induced by electron-electron interactions in anisotropic two dimensional systems. We use perturbation theory to treat, on the same footing, the regular and singular regions of the Fermi surface. It is shown that, even for weak local coupling, the self-energy presents a nontrivial behavior showing momentum dependence and interplay with the Fermi surface shape. Our scheme gives simple analytical expressions based on local features of the Fermi surface.