Electronic Structure and X‐Ray Photoelectron Spectroscopy of Wurtzite GaxAl1‐xN Solid Alloy

Band energy structure of Ga_xAl_1‐xN solid alloy (x=0.15; 0.65) is calculated. All one‐electron methods of band energy calculations (self‐consistent norm‐conserving pseudo‐potential (NCPP), linear muffin tin orbital method (LMTO) and linear combination atomic orbital (LCAO)) methods give considerable disagreement with the experimental data. We demonstrate that better agreement with experiment is achieved when the NCPP wavefunctions are orthogonalised to the core‐like states. Simultaneously additional geometry optimization improve the agreement with the optical data. We have carried out theoretical and experimental investigation of the band density of states for two representatives of the investigated wurtzite Ga_xAl_1‐xN solid alloys (with x=0.15 and 0.65).