Electronic energy gap closure and metal-insulator transition in dense liquid hydrogen
В. П. Горелов, David M. Ceperley, Markus Holzmann, Carlo Pierleoni
Abstract
A first-order liquid-liquid phase transition from molecular to atomic fluid hydrogen has been predicted to occur at high pressure below a critical temperature of $\ensuremath{\sim}$ 2000 K. Based on quantum Monte Carlo calculations, the authors study the associated metallization process. Below the critical temperature, they find a discontinuous closure of the fundamental gap, supporting a scenario where both transitions, insulator to metal and molecular to atomic fluid, coincide. Above the critical temperature, molecular dissociation is shown to set-in while the gap is still open. At higher pressures, the liquid enters a gapless, but localized, phase, indicating a crossover from the insulating to the metallic liquid.