Rare earth chalcogenide Ce₃ Te₄ as high efficiency high temperature thermoelectric material

The electronic band structures of Ce₃ Te₄ have been studied using the first-principles density-functional theory calculations. It is found that the density of states of Ce₃ Te₄ has a very high delta-shaped peak appearing 0.21 eV above the Fermi level, which mainly comes from the f orbital electrons of the rare-earth element Ce. Using the simple theory proposed by Mahan and Sofo, [Proc. Natl. Acad. Sci. U.S.A. 93, 7436 (1996)], we obtain an ideal value of zT=13.5 for Ce₃ Te ₄ at T=1200 K, suggesting that the rare-earth chalcogenide Ce ₃ Te₄ could be a promising high efficiency high temperature thermoelectric material.