Study of resistivity of amorphous binary alloy using mode-coupling method

Abstract

39-45The mode-coupling approximation in electron-phonon interaction, which has opened a new approach for the description of electrical transport in high resistor conductors, liquid transition metals and strongly disordered systems has been extended to solid amorphous binary alloys. A simplified expression for electrical conductivity of amorphous alloys has been obtained in terms of current relaxation kernel and density relaxation kernel by adding electron-phonon coupling term in the Hamiltonian. The structure factor is allowed to vary with temperature and the product of the coupling coefficient with the static structure factor has been replaced by the T-matrix in Born approximation as in extended Ziman-Evans model. A modified formula purporting variation of packing fraction with temperature and concentration has been used to derive the TCR. The same form of packing fraction has been used for structure factors as well. Also the thermoelectric power has been calculated to verify Mooij law and study its variation with temperature. The case study of NixP1-x alloy with x=0.85 and 0.75 has been undertaken and results tested for valence values z =1.03, 1.10, 1.21 at x=.85 and z =1.28, 1.33 at x=.75 with atomic volumes 75.5, 76.60 au. It has been found that the model satisfies the experimental results both qualitatively and quantitatively