Transport properties of Al–Si solid solutions: theory

Al–Si solid solutions synthesized under high pressure demonstrate striking physical properties, among which are enhanced superconductivity and peculiarities of low-temperature transport properties. To find the reason behind the latter we have performed a first-principles study of the electronic spectra and Fermi surfaces of Al–Si solid solutions. Two electronic topological transitions (ETTʹs), taking place in the system with increasing concentration of Si and pressure, have been revealed. Based on these data and the theory of ETTʹs for substitutional solid solutions we have calculated concentration dependencies of the resistivity, thermoelectric power and Hall constant. We show the results to be in quantitative agreement with experiment and to reproduce nicely the experimentally observed peculiarities.