Anomalous behaviours of the electrical resistivity of the melt of a typical III-V Ga-Sb system

The electrical resistivity, , was measured for the melt of a typical III-V semiconductor system, Ga-Sb, by the direct-current four-probe method. Similarly to the case for solid substitutional alloys, the Nordheim rule almost establishes the concentration dependence of . That is, a rather parabolic form of was obtained as a function of composition; is the deviation of the resistivity from the linear law relating the resistivities of the pure components, liquid Ga and liquid Sb. In spite of this rather simple behaviour of the concentration dependence of itself, its temperature coefficient, d /d T , shows a clear minimum at the eutectic composition and even a negative temperature coefficient was observed near the eutectic point. This negative d /d T may be the first indication for the existence of particular hidden structure, related to concentration fluctuations, in the liquid near the eutectic point. In addition, this strange behaviour of d /d T was discussed on the basis of the effective-medium theory.