Transport properties of polycrystalline Mg2Si1-ySby (0≤y<0.4)

Thermal conductivity, Seebeck coefficient, resistivity, and Hall measurements on polycrystalline Mg2Si1-ySby with 0 <= y <= 0.37 are reported. In these materials, Sb substitutes for Si in the antifluorite structure. As the Sb content increases, vacancies are formed in the lattice on Mg sites, which also contribute to variations in the transport properties. With increasing Sb content, both the absolute Seebeck coefficient and electrical resistivity first decrease, but then increase due to vacancy formation, while the thermal conductivity decreases monotonically with increasing Sb content. We investigate the lattice thermal conductivity by modeling the data using the Debye approximation in order to discern the contributions from different phonon-scattering mechanisms. We discuss the results in the context of potential thermoelectric applications.