The semiconductor-metal transition of liquid tellurium-arsenic mixtures

The Hall coefficients, R-H, conductivity, sigma, and the EXAFS spectra of l iquid As-Te mixtures containing 0-40 at.% As have been measured up to 600 d egrees C. There are three regimes: I (semiconducting state), II (strong sca ttering state) and III (metallic state) in the temperature dependence of RH From EXAFS measurement it is found that the As-Te bonds break with increas ing temperature, which coincides with a rapid decrease of R-H in regime II, and consequently the network structure of liquid As-Te mixtures is transfo rmed into a chain like structure around 500 degrees C. The structural trans formation induces the transition from a semiconductor to metal. (C) 1999 El sevier Science B.V. All rights reserved.