ICT2014 Abstracts

Mano et al. recently reported low temperature thermoelectric properties of single crystals of
type-II clathrates (K, Ba)₂₄(Ga, Sn, Vc)₁₃₆ (Vc: vacancy) (Phys. Rev. B84(2011)214101). We prepared sintered samples of K₈Ba₁₆Ga₄₀Sn₉₆ to measure the thermoelectric properties. As a result, the sample was found to have a relatively high ZT value of 0.94 at 637 K. This is comparable to that of type-VIII clathrates Ba₈Ga₁₆Sn₃₀. Also, this sample possessed the largest room temperature mobility of 140 cm²V^-1s^-1 among the reported clathrate materials except for undoped ones.