Interatomic Potentials with Electron Temperature

Abstract

Abstract In Chapters 7 and 8, the high temperature (T) properties of metals were treated in the conventional weak-coupling limit, where zero-T quantum-based interatomic (QBIPs) are applied to obtain the thermal components of thermodynamic properties in the solid as well as the liquid. In this chapter, we consider the alternative strong-coupling limit, where the ion and electron temperatures are treated on an equal footing, leading to explicit T-dependent QBIPs. Such a strong-coupling treatment can be important for narrow-band 3d and 4d transition metals near melt due to their high density of electronic states and corresponding large observed specific heats. Here the generalized pseudopotential theory (GPT) of QBIPs is first extended to finite electron temperature within the rigorous Mermin formulation of density functional theory. For a Mo prototype, T-dependent model-GPT potentials have then been developed for optimized noncanonical d bands and applied to the simulation of the high-pressure melt curve, a result that is found to be in excellent agreement with both experiment and full quantum molecular dynamics simulations.