Fermi Surface Deformation near Charge-Ordering Transition

TL;DR

This paper investigates how strong charge fluctuations near a charge-ordering transition significantly deform the Fermi surface in a 2D extended Hubbard model, revealing enhanced anisotropy in quasiparticle properties.

Contribution

It demonstrates that charge fluctuations can cause substantial Fermi surface deformation independent of nesting conditions, using a fluctuation-exchange approximation.

Findings

Fermi surface is strongly modified by charge fluctuations.

Charge fluctuations induce anisotropy in quasiparticle properties.

Deformation occurs even when CO wave vector does not match FS nesting vector.

Abstract

We study the deformation of a Fermi surface (FS) near charge-ordering (CO) transition. By applying a fluctuation-exchange approximation to the two-dimensional extended Hubbard model, we show that the FS is largely modified by strong charge fluctuations when the wave number of the CO pattern does not match the nesting vector of the FS in a noninteracting system. We also discuss the enhanced anisotropy in quasiparticle properties in the resultant metallic state.