Two-band Model with High Thermoelectric Power Factor and Its Application to FeSe Thin Film

TL;DR

This paper introduces a two-band theoretical model to achieve high thermoelectric power factor, applied to FeSe thin films, demonstrating strong temperature-dependent TE response with minimal influence from superconducting fluctuations or excitonic correlations.

Contribution

The paper presents a simple two-band model that explains high thermoelectric power factor in FeSe thin films, incorporating linear response theory and analyzing temperature dependence.

Findings

High thermoelectric power factor achieved in FeSe thin films.

Strong temperature dependence of TE response observed.

Superconducting fluctuations and excitonic correlations are not critical.

Abstract

We propose a simple theoretical model referred to as the {\it two-band model} to realize both a large Seebeck coefficient and high electrical conductivity, resulting in a high thermoelectric (TE) power factor ($PF$). Using the Kubo--Luttinger linear response theory, we apply this model to the TE response of an FeSe thin film reported by Shimizu {\it et al.} to show a high $PF$ with strong temperature dependence. The effects of superconducting fluctuations and excitonic correlations are found to not be critical.