BAND-STRUCTURE AND HIGH-PRESSURE PHASE-TRANSITION IN GAN

The Linear Muffin-Tin Orbital method is used to calculate the band structure and investigate the structural properties of GaN under high pressure. The calculated band structure for zero pressure is found to be in good agreement with existing optical data and other calculations, but the energy gap is found to be (almost) direct contrary to a recent pseuodopotential calculation. The calculated pressure coefficient of the main energy gap as well as the modulus are in very good agreement with the newest experimental data. A phase transition to the rocksalt structure is predicted to occur at 65 GPa.