Electronic structure of zinc-blende AlxGa1-xN:: Screened-exchange study

We present a first principle investigation of the electronic structure and the band gap bowing parameter of zinc-blende AlxGa1-xN using both local density approximation and screened-exchange density functional method. The calculated screened exchange local density approximation (sX-LDA) band gaps for GaN and AlN are 95% and 90% of the experimentally observed values, respectively, while LDA underestimates the gaps to 62% and 70%. In contrast to the gap itself, the band gap bowing parameter is found to be very similar in sX-LDA and LDA. Because of the difference in the conduction band structure, the direct to indirect band gap crossover is predicted to occur at different Al concentration.