AB-INITIO MOLECULAR-DYNAMICS SIMULATION OF LIQUID GA-GE ALLOYS

We report the results of ab initio molecular-dynamics simulations of l iquid Ga-Ge alloys at four different concentrations. The physical quan tities studied include the partial structure factors, bond-angle distr ibutions, self-diffusion coefficients, electronic density of states, a nd the electrical conductivity. The introduction of Ga causes a distin ct reduction of the shoulder in the structure factor of pure l-Ge. Cor respondingly, the partial structure factors, pair correlation function s, and bond angle distribution functions all show behavior characteris tic of simple liquid metals except at 80% Ge. The electronic density o f states shows a behavior consistent with the structure: it evolves fr om having a distinct pseudogap at low concentrations of Ga to being al most free-electron-like for high Ga concentrations. The calculated beh avior of the electrical conductivity agrees qualitatively with previou s calculations based on the Faber-Ziman theory of liquid alloys. The s elf-diffusion coefficients DGe-Ge and DGa-Ga are consistent with previ ous calculations and available experiments for the pure liquids. [S016 3-1829(98)00517-7].