Hidden Fermi Liquid, Scattering Rate Saturation and Nernst Effect: a DMFT Perspective

TL;DR

This paper uses dynamical mean field theory to analyze the transport properties of correlated metals, revealing a hidden Fermi liquid with unusual scattering rate behavior and deriving expressions for various transport coefficients.

Contribution

It introduces a DMFT-based framework to understand the hidden Fermi liquid and its impact on transport phenomena, including scattering rate saturation and temperature-dependent band dispersion.

Findings

Quasiparticle scattering rate remains quadratic up to high temperatures

Transport above $T_{FL}$ is dominated by temperature-dependent band dispersion

Derived expressions for resistivity, Hall angle, thermoelectric power, and Nernst coefficient

Abstract

We investigate the transport properties of a correlated metal within dynamical mean field theory. Canonical Fermi liquid behavior emerges only below a very low temperature scale $T_{FL}$. Surprisingly the quasiparticle scattering rate follows a quadratic temperature dependence up to much higher temperatures and crosses over to saturated behavior around a temperature scale $T_{sat}$. We identify these quasiparticles as constituents of the hidden Fermi liquid. The non-Fermi liquid transport above $T_{FL}$, in particular the linear-in-$T$ resistivity, is shown to be a result of a strongly temperature dependent band dispersion. We derive simple expressions for resistivity, Hall angle, thermoelectric power and Nernst coefficient in terms of a temperature dependent renormalized band structure and the quasiparticle scattering rate. We discuss possible tests of the DMFT picture of transport using ac measurements.