Semiconductor-metal transition in liquid As-Te mixtures

Abstract

EXAFS, conductivity and Hall coefficient measurements have been carried out for liquid As-Te mixtures. EXAFS analysis reveals the presence of chemical disorder marked by the existence of homopolar As-As and Te-Te pairs. At high temperature around 500 °C the network structure composed of threefold coordinated As atoms and twofold coordinated Te atoms is transformed into the twofold chain structure. The network-chain transformation is accompanied by the gradual semiconductor to metal transition which is demonstrated by the results for conductivity and Hall coefficient. The microscopic origin of the semiconductor to metal transition is discussed in connection with the structural modification.