Pressure Effect of Seebeck Coefficient for Zinc Doped Tin Clathrates

摘要

W'e measured the temperature dependence of electrical resistance (R) and thermopower (S) of Cs_8Zn_4Sn_(42) under high pressure up to 1.2 GPa. Both R and |S| at room temperature increased with pressure. We observed gap widening, irreversible |S| increasing under high pressure, which were similar to the behaviors of Cs_8Sn_(44). However, the relaxation effect of R for Cs_8Zu_4Sn_(42) was negligible in contrast with that of Cs_8Sn_(44). We found that the power factor S~2σ (σ: electrical conductivity) near room temperature decreased linearly with pressure. The results suggest that the defects in different forms played an important role in transport properties for tin cla.thra.tes under high pressure.