Pressure and composition dependence of the electronic structure ofGaAs1−xNx

The electronic band structures of ${\mathrm{GaAs}}_{1-x}{\mathrm{N}}_x$ for x =0.016 and 0.031 are calculated ab initio using a supercell approach in connection with the full-potential linear muffin-tin-orbital method. The strong nitrogen-induced modification of the conduction band structure is shown. The effects of hydrostatic pressure are examined, and the effective mass of the conduction electrons is studied as a function of pressure and Fermi energy. Strong nonparabolicity is found for the lowest conduction band which leads to an effective mass that increases with the wave number. The effect is enhanced with application of pressure, and it further depends on the nitrogen concentration. The theoretical calculations are compared to experimental data, and agreement of general trends is found.