Impact of Ferroelectric Distortion on Thermopower in BaTiO3

TL;DR

This paper explores how ferroelectric distortion in BaTiO3 can enhance thermoelectric performance by increasing the Seebeck coefficient through band structure modifications, using ab initio calculations.

Contribution

It introduces a novel approach to improve thermoelectric efficiency by leveraging ferroelectric distortion effects in transition-metal oxides.

Findings

Large Seebeck coefficient in n-type BaTiO3 due to ferroelectric distortion

Polar structural distortion alters conduction band dispersion

Carrier concentration affects Seebeck coefficient via band velocity distribution

Abstract

We present a strategy for increasing thermoelectric performance by invoking ferroelectric distortion in a transition-metal oxide. By using an ab initio calculation approach with the Boltzmann transport equation, a large Seebeck coefficient is calculated in n-type BaTiO3. The polar structural distortion causes the peculiar dispersion of the lowest conduction band, which enhances the Seebeck coefficient along the polar direction. A microscopic mechanism of carrier concentration dependence of the Seebeck coefficient is discussed in terms of the band velocity distribution in the Brillouin zone.