Thermal and transport properties of the cubic semimetal Y3Ir4Ge13: on the metallic border of thermoelectric merit

The first results of thermal and electronic transport measurements on the cubic intermetallic compound Y3Ir4Ge13 are reported. The electrical resistivity as well as the Hall coefficient show semimetallic activation behaviour. The specific heat is metallic-like at low temperatures. Towards higher temperatures the specific heat favours a description in terms of a Debye model together with Einstein modes that are attributable to details of the crystal structure of Y3Ir4Ge13. The heat conductivity is surprisingly low, only weakly temperature dependent, and predominantly from phonons. A large thermoelectric power, 38 muV K-1, is obtained at room temperature. The properties of Y3Ir4Ge13 are discussed and compared with thermoelectric materials of current interest.