Transport Properties of the Binary Type I Clathrate K8Ge44□2.

We report the synthesis and low-temperature electrical resistivity, Seebeck coefficient, and thermal conductivity of the binary type I clathrate K₈Ge₄₄□₂ (□=Ge framework vacancy). Electrical resistivity measurements indicated metallic or heavily doped semiconductor behavior, while the Seebeck was relatively high at −77 μV/K at room temperature. The thermal conductivity was very low, on the order of 1 W/m K at room temperature. This work is part of a continuing effort to investigate new compositions in open-structured and guest-framework materials for potential thermoelectric applications. [ABSTRACT FROM AUTHOR]