Condensed Matter Seminar

Abstract

Thermoelectric materials are important for spacecraft power, waste heat recovery, thermal management and cooling applications. Here I discuss the basic physics of thermoelectric effects and approaches for discovering new thermoelectric materials. A key issue is the contraindication of high thermoelectric performance, which places thermoelectrics into an interesting group of materials that includes transparent conductors, magnetic semiconductors and multiferroics. The efficiency of thermoelectric systems is limited by materials performance. This is measured by the figure of merit ZT=sS²T/k, where S is the thermopower and the other symbols have their usual meaning. ZT is therefore a composite property involving electronic and thermal transport, with high ZT favored by high conductivity, high thermopower and low thermal conductivity. However, these properties are inter-related, often to the detriment of high ZT. This talk discusses these correlations, and points out ways to overcome them.