High Thermoelectric Power Factor in a Carrier-Doped Magnetic Semiconductor CuFeS₂

Abstract

The chalcopyrite CuFeS2 is a natural magnetic semiconductor, where Fe spins order antiferromagnetically at TN = 853 K. We investigate the thermoelectric properties of the carrier-doped chalcopyrite alloys, Cu1-xFe1+xS2 with x = 0.03 and 0.05, and Zn0.03Cu0.97FeS2. All systems showed characteristic behavior of n-type degenerate semiconductors. The large Seebeck coefficient with a high carrier-density indicates enhanced carrier mass of m* = 3–6m0, where m0 is the electron mass. Consequently, the thermoelectric power factor exceeds 1×10-3 W K-2 m-1 at 400 K. We propose that utilizing magnetic semiconductor can be a new effective strategy to obtain enhanced values of the power factor.