Evaluation of anisotropic thermoelectric power of ReSi1.75

The highly anisotropic transport properties of ReSi1.75 single crystals have been evaluated with the Boltzmann transport equation under the assumption that the deformation potential acoustic phonon scattering is dominant. There is a large difference between the calculated transport properties and the measured properties along [1 0 0], while there is little difference between the calculated and the measured along [0 0 1]. The intervalley scattering mechanism is proposed as the reason of the discrepancy in the transport properties along [1 0 0]. It is also shown that the large effective mass of holes along [0 0 1] restrict the contribution of the holes in transporting the energy induced by the Seebeck effect, resulting in good thermoelectric conversion efficiency.