Electronic band structure, transport, and magnetic properties ofMo3−xRuxSb7

Abstract

Electrical and thermal transport properties, including thermopower, electrical resistivity, thermal conductivity, as well as Hall effect and magnetic susceptibility measurements have been carried out on polycrystalline ${\text{Mo}}_{3\ensuremath{-}x}{\text{Ru}}_{x}{\text{Sb}}_{7}$ samples for nominal concentrations $x=0.0$, 0.25, 0.50, and 1.0 in the 2--350 K temperature range. Further insight into the variations in the electronic band structure as the Ru content increases has been gained by calculating dispersion curves and total and partial densities of states using the Korringa-Kohn-Rostoker method with the coherent-potential approximation. This theoretical analysis has revealed a rigidlike behavior of the electronic structure, synonymous of a shift in the Fermi level toward the valence band edge as $x$ increases. Transport properties investigations have provided compelling experimental evidence for this picture, i.e., an increase in both the electrical resistivity and thermopower which is concomitant to a decrease in the charge-carrier concentration with $x$. Magnetic susceptibility data have shown that the magnetic interactions displayed by ${\text{Mo}}_{3}{\text{Sb}}_{7}$ are progressively suppressed by increasing the ruthenium concentration. In addition, increasing $x$ leads to a surprising enhancement of the lattice thermal conductivity that may be due to the suppression of strong phonon-dimer interactions exhibited by ${\text{Mo}}_{3}{\text{Sb}}_{7}$.