Transport and thermal properties of single- and polycrystalline NiZr_(0.5)Hf_(0.5)Sn

摘要

The thermoelectric properties of a Heusler compound with NiZro.5Hfo.5Sn composition were studied. A comparison of the properties of a single crystal and a polycrystal was carried out by measurements of the electrical conductivity, Seebeck coefficient, and thermal conductivity. The transport properties are directly compared to the valence band electronic structure measured by photoelectron spectroscopy. The single crystal shows a higher figure of merit (Zr=0.1) at room temperature which originates from the high electrical conductivity that is mediated by "in-gap" states observed by photoemission spectroscopy.