Band structure and pressure-induced metallic transition in iodine - GW calculation

We have studied the band structure and the band gap closure in phase I of solid iodine under high pressure, using the methods based on the quasiparticle theory, i.e. GW approximation. Our calculations show that the band gap in the Cmca structure, which is the structure of the phase I of solid iodine, closes around 20GPa. This pressure is near the upper boundary of phase I. We discuss the possible metallic transition in the molecular phase of solid iodine and the possible changes of the crystal structure.