Quasiparticle Mass Enhancement and Fermi Surface Shape Modification in Oxide Two-Dimensional Electron Gases

TL;DR

This paper presents a model for oxide 2D electron gases showing how electron-electron interactions increase quasiparticle masses and alter Fermi surface shape, with implications for understanding correlated electron systems.

Contribution

It introduces a qualitative model capturing electron-electron interactions in oxide 2D electron gases, highlighting mass enhancement and Fermi surface modifications.

Findings

Coulomb interactions significantly increase quasiparticle effective masses.

Interactions reshape the Fermi surface, reducing anisotropy.

Perturbative $GW$ approximation effectively describes these effects.

Abstract

We propose a model intended to qualitatively capture the electron-electron interaction physics of two-dimensional electron gases formed near transition-metal oxide heterojunctions containing $t_{2g}$ electrons with a density much smaller than one electron per metal atom. Two-dimensional electron systems of this type can be described perturbatively using a $GW$ approximation which predicts that Coulomb interactions enhance quasiparticle effective masses more strongly than in simple two-dimensional electron gases, and that they reshape the Fermi surface, reducing its anisotropy.