Electronic transport coefficients from ab initio simulations and application to dense liquid hydrogen

Using Kubo's linear response theory, we derive expressions for the frequency-dependent electrical conductivity (Kubo-Greenwood formula), thermopower, and thermal conductivity in a strongly correlated electron system. These are evaluated within ab initio molecular dynamics simulations in order to study the thermoelectric transport coefficients in dense liquid hydrogen, especially near the nonmetal-to-metal transition region. We also observe significant deviations from the widely used Wiedemann-Franz law which is strictly valid only for degenerate systems and give an estimate for its valid scope of application towards lower densities

CRITICAL PHENOMENA AND THE METAL-NONMETAL TRANSITION IN LIQUID METALS

Experimental results for fluid metals near the liquid-vapour critical point show that profound changes in the electronic structure of fluid metals occur in that region. A gradual transition from metallic to non-metallic behaviour occurs with decreasing density, which manifests itself in a corresponding strong thermodynamic state dependence of the interparticle interaction. The existence of this transition noticeably influences the thermodynamic features of the vapour-liquid phase transition of metals. Another equally important aspect of the problem is the size-dependent gradual evolution of metallic properties in isolated, microscopic metal clusters which clearly must be part of any detailed consideration of the liquid-vapour critical point phase transition of metals