Lawrence Berkeley National Laboratory

The band gap bowing and the electron localization of GaxIn1-xN are calculated using both the local density approximation (LDA) and screened-exchange local density functional (sX-LDA) methods. The calculated sX-LDA band gaps are in good agreement with the experimentally observed values, with errors of -0.26 and 0.09 eV for bulk GaN and InN, respectively. The LDA band gap errors are 1.33 and 0.81 eV for GaN and InN, in order. In contrast to the gap itself, the band gap bowing parameter is found to be very similar in sX-LDA and LDA. We identify the localization of hole states in GaxIn1-xN alloys along In-N-In chains. The predicted localization is stronger in sX-LDA.