Hard x-ray photoemission spectroscopy of rhenium substituted higher manganese silicides.

We have investigated the electronic structure of a potential thermoelectric material, higher manganese silicide, and its solid solutions with supersaturated Re by means of hard x-ray photoemission spectroscopy. The unusual Re substitution dependence of thermoelectric properties in the higher manganese silicide, reducing the electrical resistivity without altering the Seebeck coefficient, can be explained in terms of the variation of the density of states at the Fermi level and its energy derivative. Such an electronic structure variation contributes to an improvement in the thermoelectric performance in combination with the suppressed thermal conductivity. [ABSTRACT FROM AUTHOR]