Resonant enhancement of thermoelectric properties by correlated hopping for the Falicov-Kimball model on Bethe lattice

TL;DR

This paper investigates how correlated hopping influences thermoelectric properties in the Falicov-Kimball model on the Bethe lattice, revealing resonant enhancements in transport due to singularities in the two-particle transport function.

Contribution

It provides exact solutions for the density of states and transport functions, showing how tuning parameters near resonance significantly boosts thermoelectric performance.

Findings

Transport function exhibits singularities at resonance

Electrical and thermal conductivities increase near resonance

Localization occurs with reduced hopping amplitude, forming a narrow band

Abstract

The effect of correlated hopping on the charge and heat transport of strongly correlated particles is studied for the Falicov-Kimball model on the Bethe lattice. Exact solutions for the one particle density of states (DOS) and two particle transport function (the "quasiparticle" scattering time) are derived using dynamical mean field theory. For a wide range of the correlated hopping, the transport function exhibits singularities due to the resonant two-particle contribution, whereas the one particle DOS does not show any anomalous features. By tuning the number of itinerant electrons, so as to bring the Fermi level close to the resonant frequency, we get a large increase of the electrical and thermal conductivities, and the thermoelectric power. When the hopping amplitude between the occupied sites is reduced sufficiently, the itinerant electrons localize in the clusters of sites occupied by $f$ electrons. This gives rise to an additional narrow band in the DOS between the lower and upper Hubbard bands, but has only a minor effect on the thermoelectric properties.