Doping dependence of thermopower and thermoelectricity in strongly correlated systems

TL;DR

This paper develops a unified theoretical framework to understand thermoelectric transport in doped Mott insulators, revealing that certain correlated materials can achieve high power factors comparable to top semiconductors at room temperature.

Contribution

It applies a unified theory in the atomic and Heikes limit to explain thermoelectric properties of doped Mott insulators, highlighting their potential for high thermoelectric efficiency.

Findings

Correlated materials can have high power factors at room temperature.

The theory explains transport in sodium cobaltate and similar materials.

Optimal electron filling enhances thermoelectric performance.

Abstract

The search for semiconductors with high thermoelectric figure of merit has been greatly aided by theoretical modeling of electron and phonon transport, both in bulk materials and in nanocomposites. Recent experiments have studied thermoelectric transport in ``strongly correlated'' materials derived by doping Mott insulators, whose insulating behavior without doping results from electron-electron repulsion, rather than from band structure as in semiconductors. Here a unified theory of electrical and thermal transport in the atomic and ``Heikes'' limit is applied to understand recent transport experiments on sodium cobaltate and other doped Mott insulators at room temperature and above. For optimal electron filling, a broad class of narrow-bandwidth correlated materials are shown to have power factors (the electronic portion of the thermoelectric figure of merit) as high at and above room temperature as in the best semiconductors.