Neutron diffraction of liquid arsenic–tellurium mixtures near the semiconductor–metal transition

Abstract Neutron scattering measurements have been carried out for liquid As–Te mixtures containing 10, 20 and 30 at.% As in the temperature range between 400 and 600 °C. The local structure was analyzed by combining the information available from our previous EXAFS results. The partial coordination number for As–Te, n As–Te , for the mixture containing 20 at.% As decreases from 3.0–2.5 at 400 °C to 2.0–1.7 at 600 °C, suggesting that a `network-chain' structural transformation occurs on the semiconductor to metal transition at high temperature. We propose that the first sharp diffraction peak observed around 1.4 A −1 in S ( Q ) indicates the presence of small chain clusters. It is found that the position of the second peak of g ( r ) shifts to smaller r at high temperature, which leads to volume contraction.