High frequency thermoelectric response in correlated electronic systems

TL;DR

This paper develops a formalism to evaluate the high-frequency thermoelectric power in strongly correlated materials, highlighting differences between static and high-temperature limits near the Mott transition.

Contribution

It introduces a general formalism for high-frequency thermoelectric response applicable to correlated systems, and assesses the validity of approximating static thermoelectric power by its high-temperature limit.

Findings

$S^*$ approximates $S_0$ well at high temperatures.

Differences between $S^*$ and $S_0$ are significant near the Mott transition.

Formalism is compatible with first principles LDA+DMFT calculations.

Abstract

We derive a general formalism for evaluating the high-frequency limit of the thermoelectric power of strongly correlated materials, which can be straightforwardly implemented in available first principles LDA+DMFT programs. We explore this formalism using model Hamiltonians and we investigate the validity of approximating the static thermoelectric power $S_0$, by its high-temperature limit, $S^*$. We point out that the behaviors of $S^*$ and $S_0$ are qualitatively different for a correlated Fermi liquid near the Mott transition, when the temperature is in the coherent regime. When the temperature is well above the coherent regime, e.g., when the transport is dominated by incoherent excitations, $S^*$ provides a good estimation of $S_0$.