Thermal and transport properties of the cubic semimetal Y ₃Ir₄Ge₁₃: 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 Y₃Ir ₄Ge₁₃. The heat conductivity is surprisingly low, only weakly temperature dependent, and predominantly from phonons. A large thermoelectric power, 38νVK^-1, is obtained at room temperature. The properties of Y₃Ir₄Ge₁₃are discussed and compared with thermoelectric materials of current interest.