Calculated structural, electronic and optical properties of Ga-based semiconductors under pressure

The structural, electronic and optical properties of GaP, GaAs and GaSb at ambient and under hydrostatic pressure have been calculated using the full potential linear augmented plane wave (FP-LAPW) method. The calculated lattice constant, bulk modulus and its pressure derivative are compared with available experimental data. The first and second order pressure coefficients for the (Γ-Γ) energy gaps and hydrostatic deformation potential shows agreement with measurement. The linear pressure coefficients of the transition (Γ-Γ) increases significantly as anion atomic number increases (GaP→GaAs→GaSb). The magnitude of linear pressure coefficient of the transition (Γ-X) are small and usually negative. The variation of linear pressure coefficient of the transition (Γ-L) are relatively small and follow similar trend as (Γ-Γ). Overall the calculated linear and nonlinear pressure coefficients show good agreement with the experimental data. The obtained dielectric function, refractive index, extinction coefficient and reflectivity are compared with measured data and show qualitatively good agreement.