Electronic Structures and Thermoelectric Properties of Sb-Doped Type-VIII Clathrate Ba8Ga16Sn30

The type-VIII clathrate Ba8Ga16Sn30 shows a high figure of merit (ZT) in the middle temperature range 470-670 K. ZT enhancement through Sb doping has recently been reported in p-type Ba8Ga16Sn30. In this study, calculations to determine the electronic structures and thermoelectric properties of Sb-doped Ba8Ga16Sn30 are performed using the WIEN2k code. The energy derivative of density of states [partial derivative rho(epsilon)/partial derivative epsilon](epsilon=EF) for valence band is lower in the Sb-doped Ba8Ga16Sn30 than in non-Sb-doped one, though the density of states [rho(epsilon)](epsilon=EF) of both system are almost the same as that for Ba8Ga16Sn30. Except for the signs, the calculated Seebeck coefficients for the p- and n-type Sb-doped and non-Sb-doped Ba8Ga16Sn30 are similar. [doi:10.2320/matertrans.E-M2012807]