The Band Structure of Solid Iodine under Pressure and the Mechanism of the Pressure-Induced Insulator-to-Metal Transition

The band structures of solid iodine under ambient pressure and 15.3 GPa were calculated with the ab initio pseudopotential method. The apparently complicated band structures have been resolved by a detailed analysis, revealing the mechanism of the band overlap which causes the pressure-induced insulator-to-metal transition: The interlayer interaction as well as the interaction between the third-nearest neighbor atoms is responsible for the band overlap. The effect of the spin-orbit interaction on the band overlap is also discussed