A First-principles approach to predict Seebeck coefficients: Application to La3-xTe4

TL;DR

This paper introduces a first-principles, parameter-free method to predict Seebeck coefficients based on electronic density-of-states, validated on La3-xTe4 with results matching experimental data.

Contribution

It derives a rigorous relation between Seebeck coefficient and chemical potential from thermodynamics and develops a first-principles calculation formalism.

Findings

Accurate prediction of Seebeck coefficients for La3-xTe4 using the new method.

Excellent agreement between calculated and experimental temperature dependences.

Validation of the approach with the rigid band approximation.

Abstract

Theoretical descriptions of the Seebeck coefficient in terms of the differential electrical conductivity given by Cutler and Mott is the foundation of later works in terms of transmission function from the thermoelectric transport theory. On the other hand, recent studies in the literature have shown the relation between the Seebeck coefficient and chemical potential of electrons. In this work, this relation is rigorously derived from fundamental thermodynamics, and an formalism for the parameter-free calculation of the Seebeck coefficient based on the electronic density-of-states from first-principles calculations is presented. Numerical results are given using the n-type La3-xTe4 thermoelectric material as the prototype. With the rigid band approximation, the calculated temperature dependences of the Seebeck coefficients of La3-xTe4 as a function of carrier concentration show excellent agreements with experimental data.