Pressure Induced Metallization in the ε Phase of Solid Oxygen by ab initio Pseudopotential Plane-Wave Calculations

We perform an ab initio study on the electronic structure and charge density of the c-oxygen under high pressure, which is obtained by powder x-ray diffraction experiment recently. Our results show that the hybridization among the σg^＊, πu and πg^＊ bands in the e-oxygen are not significant even at megabar pressure. Pressure-induced metallization occurs due to the band overlapping near the Fermi level at about 50 GPa. A new network along the b-axis is formed and the 08 characteristic in the e phase disappears above 50 GPa even though the symmetry remains unchanged.