Localized states and thermoelectric properties of vacancy-containing Sn-based clathrate compounds

一些热电笼状化合物的骨架中有空位。这种空位通常影响它们的能带结构，而能带结构决定了它们的热电性能。因此，有可能通过控制此类材料的空位结构来改善热电性能。我们研究了笼状化合物K8Sn44-2(-：空位)的空位结构、热电性质和能带结构。包合物样品在320K时发生有序-无序相变，其电导率和功率因数几乎增加了10倍。

Some thermoelectric clathrate compounds possess vacancies in their frameworks. Such vacancies usually affect their band structures, which dominate their thermoelectric properties. Thus, there is a possibility of improving thermoelectric properties by the control of vacancy-structures of such materials. We have studied the vacancy-structures, thermoelectric properties, and band structures of the clathrate compounds K8Sn44□2(□: vacancy). The clathrate samples exhibited order-disorder phase transitions at 320 K, where their electrical conductivities and power factors almost increased tenfold.