Metallization and positive pressure dependency of bandgap in solid neon.

The metallization of neon remains a controversial problem as there is no consensus in theoretical simulations and no experimental verification. In this work, the insulator-to-metal transition in fcc solid neon at high pressure was revisited with a coupling of the all-electron full-potential linear augmented-plane wave (FP-LAPW) method and the GW correction to avoid the potential unreliability of pseudopotential under high pressure and correct the inaccurate energy gaps caused by local density or generalized gradient approximation of the exchange-correlation. This FP-LAPW + GW calculation predicts that the bandgap closes at a density of 88.3 g/cm3 and a pressure of 208.4 TPa. Moreover, the reported positive pressure dependency of energy gap (increases with increasing density) for solid neon in 1.5-10.0 g/cm3 was confirmed with our FP-LAPW calculations, and the underlying mechanism was first revealed based upon analysis of the charge density distribution and the electron localization function. The results of this research will provide a valuable reference for future high pressure experiments and shed new insight into the planetary interiors.