Pressure dependence of optoelectronic properties of GaN in the zinc-blende structure

The optoelectronic properties of GaN with zinc-blende structure under hydrostatic pressure up to 120 kbar are investigated employing the empirical pseudopotential method. The pressure coefficients of several critical-point band gaps are calculated and found to be in good agreement with the available experimental data. The refractive index decreases linearly with increasing pressure showing a negative pressure coefficient. At zero pressure, the agreement between our calculated optical dielectric constant and the existing experimental data depends on the model used for calculating the refractive index.