EXPLICIT TREATMENT OF THE GALLIUM 3D ELECTRON IN GAN USING THE PLANE-WAVE PSEUDOPOTENTIAL METHOD

The plane-wave pseudopotential (PWPP) method has been used to calculat e structural and electronic properties of wurtzite and zinc-blende GaN . In contrast to previous studies using the PWPP method, the gallium 3 d electrons were treated as valence electrons. This yields larger latt ice constants and smaller energy gaps as compared with previous PWPP r esults. For wurtzite, the three structure parameters were found to be a = 3.162 angstrom, c = 5.142 angstrom, and u = 0.377. For zinc blende , the cubic lattice constant was found to be a0 = 4.460 angstrom. The lattice constants are about 1 % smaller than measured values and the c ubic lattice constant is within about 0.2% of results from full-potent ial all-electron calculations. This study demonstrates that it is both possible and practical to treat gallium 3d electrons explicitly using the PWPP method.