Metastable conducting crystalline hydrogen at high pressure

The quantum molecular dynamics method within the density functional theory has been used to calculate the equation of state, pair correlation function, and static electrical conductivity of solid hydrogen in the region of formation of a conducting phase. Hysteresis has been revealed on the density dependence of the pressure at a temperature of $100$ K under compression and subsequent tension. The overlapping of branches of the isotherms of the molecular and nonmolecular phases of solid hydrogen corresponds to the region of existence of metastable states. The width of this region is $275$ GPa. It has been shown that conducting crystalline nonmolecular hydrogen with $P2_1/c$ symmetry can exist at extension to a pressure of $350$ GPa.