Spectral properties in the charge density wave phase of the half-filled Falicov-Kimball Model

TL;DR

This paper investigates the spectral properties of the charge density wave phase in the half-filled Falicov-Kimball model using dynamical mean field theory, revealing non-traditional behaviors such as gapless CDW phases.

Contribution

It provides detailed spectral function analysis in the CDW phase, highlighting deviations from mean-field predictions and the influence of non-Fermi liquid behavior.

Findings

Identification of a CDW phase without a spectral gap.

Observation of non-Fermi liquid effects near the phase boundary.

Deviation from mean-field proportionality between gap and order parameter.

Abstract

We study the spectral properties of charge density wave (CDW) phase of the half-filled spinless Falicov-Kimball model within the framework of the Dynamical Mean Field Theory. We present detailed results for the spectral function in the CDW phase as function of temperature and $U$. We show how the proximity of the non-fermi liquid phase affects the CDW phase, and show that there is a region in the phase diagram where we get a CDW phase without a gap in the spectral function. This is a radical deviation from the mean-field prediction where the gap is proportional to the order parameter.