Thermoelectric Properties of Antiperovskite Calcium Oxides Ca3PbO and Ca3SnO

TL;DR

This study investigates the thermoelectric properties of polycrystalline Ca3Pb1-xBixO and Ca3SnO antiperovskite oxides, revealing Ca3SnO's promising high thermoelectric power and metallic behavior, indicating potential for thermoelectric applications.

Contribution

First detailed analysis of thermoelectric properties in Ca3Pb1-xBixO and Ca3SnO antiperovskites, highlighting Ca3SnO's high power factor and metallic conduction characteristics.

Findings

Ca3SnO exhibits metallic resistivity and high thermoelectric power.

Ca3SnO has a carrier density of ~10^19 cm^-3 and high mobility.

Potential multivally electronic structure enhances thermoelectric prospects.

Abstract

We report the thermoelectric properties of polycrystalline samples of Ca3Pb1-xBixO (x = 0, 0.1, 0.2) and Ca3SnO, both crystallizing in a cubic antiperovskite-type structure. The Ca3SnO sample shows metallic resistivity and its thermoelectric power approaches 100 uV K-1 at room temperature, resulting in the thermoelectric power factor of Ca3SnO being larger than that of Ca3Pb1-xBixO. On the basis of Hall and Sommerfeld coefficients, the Ca3SnO sample is found to be a p-type metal with a carrier density of ~1019 cm-3, a mobility of ~80 cm2 V-1 s-1, both comparable to those in degenerated semiconductors, and a moderately large hole carrier effective mass. The coexistence of moderately high mobility and large effective mass observed in Ca3SnO, as well as possible emergence of a mutivalley electronic structure with a small band gap at low-symmetry points in k-space, suggests that the antiperovskite Ca oxides have strong potential as a thermoelectric material.