Temperature Dependence of Thermopower in Strongly Correlated Multiorbital Systems

TL;DR

This study investigates how temperature affects thermopower in multiorbital Hubbard models, revealing non-monotonic behavior and sign reversal due to electron interactions and crystal field effects, with implications for material properties.

Contribution

It introduces a detailed analysis of thermopower temperature dependence in multiorbital systems using dynamical mean-field theory, highlighting the roles of Coulomb interaction, Hund coupling, and crystal field splitting.

Findings

Thermopower exhibits non-monotonic temperature dependence.

Sign reversal of thermopower occurs due to interactions.

Implications for material thermoelectric properties.

Abstract

Temperature dependence of thermopower in the multiorbital Hubbard model is studied by using the dynamical mean-field theory with the non-crossing approximation impurity solver. It is found that the Coulomb interaction, the Hund coupling, and the crystal filed splitting bring about non-monotonic temperature dependence of the thermopower, including its sign reversal. The implication of our theoretical results to some materials is discussed.