Total and partial structure factors, compressibility, diffusion coefficients and other associated properties of an Ag-Se semiconducting alloy

Abstract

Ashcroft-Langreth partial structure factors were computed using a Lebowitz solution of hard sphere mixtures perturbed by a square well potential. The potential parameters were obtained from the measured structure factor. Both the partial and total structure factors were Fourier transformed to give the partial and total radial distribution functions, from which the partial and total numbers of nearest neighbours were evaluated. Using the peaks of the radial distribution functions the nearest-neighbour distance was obtained. The results so obtained are found to be in good agreement with experimentally determined values. The Bhatia-Thoronton correlation functions S_NN(k), S_CC(k) and S_NC(k), were calculated. It was found that S_NN(k) gives a maximum at a similar value of k as S_Total(k), as has been observed previously for the Ca_0.6Ag_0.4 alloy. The compressibility, calculated using Kirkwood-Buff's equation, even though it appears to be high, is attributed to the migration of silver atoms into voids in the liquid selenium. The self-diffusion coefficients were calculated, and that for silver was found to be higher than that for selenium. These values are also attributed to the migration of the heavy silver atoms into the voids of the comparatively less heavy selenium.