First principles search for $n$-type oxide, nitride, and sulfide thermoelectrics

TL;DR

This study uses high-throughput first principles calculations to identify promising n-type oxide, nitride, and sulfide thermoelectric materials with high power factors and low thermal conductivity, addressing a key challenge in thermoelectric research.

Contribution

It introduces a comprehensive computational screening approach for discovering high-performance n-type thermoelectrics among oxides, nitrides, and sulfides, revealing multiple promising candidates.

Findings

Identified materials with high density of states and dispersive bands.

Many candidates exhibit low thermal conductivity.

Mechanisms for high power factors vary among materials.

Abstract

Oxides have many potentially desirable characteristics for thermoelectric applications, including low cost and stability at high temperatures, but thus far there are few known high $zT$ $n$-type oxide thermoelectrics. In this work, we use high-throughput first principles calculations to screen transition metal oxides, nitrides, and sulfides for candidate materials with high power factors and low thermal conductivity. We find a variety of promising materials, and we investigate these materials in detail in order to understand the mechanisms that cause them to have high power factors. These materials all combine a high density of states near the Fermi level with dispersive bands, reducing the trade-off between the Seebeck coefficient and the electrical conductivity, but they do so for several different reasons. In addition, our calculations indicate that many of our candidate materials have low thermal conductivity.