Self-energy corrections to anisotropic Fermi surfaces

TL;DR

This paper investigates how electron-electron interactions deform the Fermi surface in anisotropic 2D systems, providing analytical expressions and highlighting complex momentum-dependent effects relevant to strongly correlated materials.

Contribution

It offers a unified analytical approach to evaluate self-energy corrections on anisotropic Fermi surfaces, considering both regular and singular regions simultaneously.

Findings

Self-energy exhibits non-trivial momentum dependence.

Deformations depend on local Fermi surface features.

Results align with experimental and theoretical data.

Abstract

The electron-electron interactions affect the low-energy excitations of an electronic system and induce deformations of the Fermi surface. These effects are especially important in anisotropic materials with strong correlations, such as copper oxides superconductors or ruthenates. Here we analyze the deformations produced by electronic correlations in the Fermi surface of anisotropic two-dimensional systems, treating the regular and singular regions of the Fermi surface on the same footing. Simple analytical expressions are obtained for the corrections, based on local features of the Fermi surface. It is shown that, even for weak local interactions, the behavior of the self-energy is non trivial, showing a momentum dependence and a self-consistent interplay with the Fermi surface topology. Results are compared to experimental observations and to other theoretical results.