First-principles study of conducting behavior of warm dense neon

Abstract

The energy gap of solid neon increases with density, which is an opposite density dependency compared to other noble gases. In order to investigate whether this abnormal phenomenon survives in the warm dense region, where the conducting behavior is closely related to the energy gap, we calculated the electrical conductivity of fluid neon for temperatures of 103–105 K and densities of 1.50–10.0 g/cm3 with a first-principles method. Temperature and density dependencies of conductivity in this region were analyzed. The results indicate that the conducting behavior is sensitive to the temperature; there is a significant increase in the direct current (dc) conductivity from 10 000 to 20 000 K. Contrary to other noble gases, we found an abnormal density dependency of dc conductivity, which decreases with increasing density at a given temperature. This phenomenon is due to the elevating localization of electrons and the broadening of the energy gap based on the analyses of charge density distribution and electronic structure under these extreme conditions. Finally, an insulating-conducting fluid phase diagram was constructed using our simulation results, which confirmed the conclusion of the latest experiment results.