Introduction to Modeling Thermoelectric Transport at High Temperatures

Abstract

This chapter provides experimentalists a basic outline for analyzing/modeling thermoelectric transport at high temperatures. The single parabolic band (SPB) model is a powerful analytical tool when investigating thermoelectric transport. The SPB model is something of a diagnostic tool for both overall thermoelectric efficiency and the existence of more complex transport behavior. Most high-performance thermoelectric materials are heavily doped semiconductors with transport properties that appear more similar to metals than semiconductors. For instance, Density functional theory (DFT) calculations predicted n-type LiZnSb to have large thermoelectric efficiency. With the DFT results for band offsets and degeneracy as a starting point, a multiparabolic band model can be pursued. The SPB model discussed hides the influence of band degeneracy within the effective mass. The effective onset temperature depends on the carrier density, where a low carrier density promotes the influence of the bipolar conduction at lower temperatures.