Anomalous thermopower in the organic compoundθ−(BEDT-TTF)2RbM(SCN)

Abstract

We have investigated the thermopower in the organic compound -͑BEDT-TTF͒ 2 RbM͑SCN͒ 4 ͑M =Zn,Co͒ in both its normal and rapidly cooled states. The anomalous temperature dependence of the thermopower is found to extend into the rapidly cooled state and reveals that the charge carriers exhibit both localized and itinerant behaviors. We propose a simple model that captures this feature on the basis of an extended Hubbard model.

Potential of Organic Materials for the Application to Thermoelectric Generators

“…Many of organic conducting and semiconducting materials are, in this sense, promising as thermoelectric conversion materials because they have very large Seebeck coefficients, over 1 mV/K [1,2], and small thermal conductivities. Recently, many excellent works on thermoelectric properties of organic materials have been reported [3][4][5][6]. However, P or ZT values in these reports are still insufficient for practical applications and, moreover, there is no comprehensive study over wide class of organic materials.…”