We report the synthesis and temperature dependent transport properties of a new type II germanium clathrate, Cs8Na16Cu5Ge131 (space group Fd3m; a = 15.42000(9) ) . In comparison to the parent compound Cs8Na16Ge136, Cu substitution for Ge on the clathrate framework was found to increase both the electrical resistivity and Seebeck coefficient, while reducing the thermal conductivity. The results are consistent with partial charge compensation due to Cu substitution for Ge. In addition to presenting possibilities for new compositions, framework substitution in type II clathrates may offer a route to control of the transport properties of these materials, offering potential candidates for thermoelectric applications.
Citation: Journal of Alloys and Compounds
Pub Type: Journals
Cproperty5Ge131, structure, thermoelectric, type II clathrates