Structurally induced insulator-metal transition in solid oxygen : A quasiparticle investigation

Structural phase transition of solid oxygen has been investigated by using ab initio calculations based on density functional theory. We found sudden jumps in structural parameters at the transition pressure, which confirm that the epsilon (epsilon) phase undergoes a first-order isostructural phase transformation to the zeta (epsilon) phase. In particular, this happens without any molecular dissociation. Using the GW approximation to calculate the band-gap closure under high pressure, we show that the structural transition is accompanied by an insulator-metal transition, contrary to a standard density functional calculation which predicts a metallization at a much lower pressure in the epsilon phase.
QC 20100525