Experimental thermoelectric power of liquid silver-germanium alloys interpreted with an analytical energy-dependent calculation

The absolute thermoelectric power of liquid Ag-Ge alloys has been measured as a Function of temperature over the whole phase diagram in 10 at.% steps, from the liquidus to 1150 degrees C. To interpret these original measureme nts we present an analytical expression of the thermoelectric power of the liquid alloys within the extended Faber-Ziman formalism in terms of partial structure factors and t-matrix formulation including, for the first time t o our knowledge, an analytical expression of the energy-dependent contribut ion. The experimental first peak asymmetry of both germanium and silver str ucture factors cannot be reproduced with hard spheres. The Silbert-Young (1 976, Phys. Lett. A, 58, 469) square-well potential describes them better fo r pure metal. To minimize the uncertainty in the knowledge of the partial s tructure factors in the electronic transport properties of liquid metals, w e used the same model extended to alloys by Gopala Rao and Das (1987, Phys. Rev. B, 36, 6325). The muffin-tin potential used in this calculation to de termine the t matrix is derived both from a screened ionic and from a neutr al atomic potential.