LIQUID-METAL SEMICONDUCTOR TRANSITIONS

At high temperatures in liquids, the transition from metallic to semiconducting behaviour is not well defined, with the consequence that the term liquid semiconductor has often been assigned to a wide range of poorly conducting liquids. Recently, by careful consideration of the Kubo-Greenwood expressions with a model-energy-dependent conductivity. Sigma(E), a narrower definition of a true semiconductor was proposed in terms Of limiting values of the conductivity and thermopower. In this paper, the extension of this framework is considered, incorporating chemical information (in the form of a model density of states) from which predictions of the composition dependence of sigma and S can be made. Examples for typical systems are given. The highly unusual cases of liquid Ag2Se and Ag2S are also considered showing how their behaviour may be understood within this framework.