Structural inhomogeneity and valence fluctuations in IIIb-Te liquid semiconductors

An inhomogeneous structure model is applied to liquid Ga 2 Te 3 to account for the dependence of its physical properties. The electronic properties are analysed in terms of an effective-medium percolation theory with the volume fraction of the metallic domains determined from Knight shift data. The temperature dependence of the molar volume and the total structure factor can be explained consistently within the same framework. The results indicate that liquid Ga 2 Te 3 consists of two kinds of domains, non-metallic and metallic, with different structures. As in the case of In 2 Te 3 the former has a structure similar to the defect zincblende structure of the solid. From analysis of the pair distribution function for the metallic domain, it is inferred that the dissociation process Ga 2 Te 3 to 2GaTe+Te occurs. Valence fluctuations of the metallic elements are proposed to interpret the temperature and composition dependence of the physical properties of liquid IIIb (Al, Ga, In, Tl)-Te systems. The well known plot of nuclear spin relaxation against conductivity by Warren (1971) should be reinterpreted.