Potential energy contribution to the thermopower of correlated electrons

TL;DR

This paper derives a formula for the thermopower in correlated electron systems that separates potential and kinetic energy contributions, aiding understanding of correlation effects on the Seebeck coefficient.

Contribution

It introduces a new formula for thermopower in Hubbard-like models that isolates potential and kinetic energy effects, improving analysis of correlation impacts.

Findings

Potential and kinetic energy contributions nearly cancel in intermediate and strong correlation regimes.

The derived formula enables separate analysis of energy contributions to thermopower.

Application to the Hubbard model via dynamical mean-field theory demonstrates the formula's utility.

Abstract

Certain classes of strongly correlated systems promise high thermopower efficiency, but a full understanding of correlation effects on the Seebeck coefficient is lacking. This is partly due to limitations of Boltzmann-type approaches. One needs a formula for the thermopower that allows separate investigations of the kinetic and potential energy contributions to the evolution with temperature and doping of the thermopower. Here we address this issue by deriving for Hubbard-like interactions a formula for the thermopower that separates the potential from the kinetic energy contribution and facilitates a better understanding of correlation effects on the Seebeck coefficient. As an example, the thermopower of the one-band Hubbard model is calculated from dynamical mean-field. For interactions in both the intermediate and strong correlation limit, the contributions from kinetic and potential energy nearly cancel.