Thermopower in correlated systems

Abstract

Novel correlated materials discussed recently such as sodium cobaltate Na x CoO 2and iron antimonide FeSb 2show considerable promise for attaining high values of thermopower. These extend the limits set by standard semiconducting materials such as bismuth telluride Bi 2 Te 3. Understanding the scale of thermopower and its dependence on material properties is a difficult task, since the Kubo formulas are somewhat opaque. We have developed two alternative approximate formulas that are easier to interpret, while capturing the many body enhancements of thermopower. These are the high frequency Seebeck coefficient S -and the Kelvin formula S Kelvin published recently. This article provides a brief guide to these alternate formulas together with a delineation of their domain of usefulness. © 2013 Springer Science+Business Media Dordrecht.