Electrical conductivity of a tight-binding hard-sphere model for hot fluid metals -: art. no. 024203

Hot fluid metals are represented using a tight-binding hard-sphere model. Various treatments of the electrical conductivity of those disordered systems are presented and results are compared for equilibrium ionic configurations near the liquid-vapor phase coexistence. The configurations are obtained from self-consistent Monte Carlo simulations, with the cohesive energy being due to exact calculations of the valence electron delocalization. The disorder in the electronic hopping elements arises from that of the ionic positions, since the hopping is assumed to decay exponentially with distance. Calculated values of the electrical conductivity are found to span several orders of magnitude along the liquid-vapor coexistence curve, from typical metallic values in the low-temperature dense liquid metal, to a percolation-limited transition, to an insulator on the vapor branch. We compare the results based on the Kubo-Greenwood treatment, formulated appropriately for the model, with those of a "mesoscopic" approach based on the Green's function method for the quantum-coherent transport between two voltages leads, and examine results from two versions of the randomized phase model, which assumes a rapid decay of the quantum coherence. The various conductivity results are also compared with the experimental data for cesium.