Formation Energies and Electronic Structures of Native Defects in GaN

The electronic structures and the formation energies of native point defects in cubic GaN have been studied via the linear muffin-tin orbital method. The results show that the nitrogen vacancy is the dominant defect in the intrinsic cubic GaN. Among the antisites and interstitial defects, it is found that a tetrahedral interstitial nitrogen atom surrounded by four Ga atoms N_TGa is most easily formed, and the formation energy of N_GaNGa antisite is much less than that of GaN antisite. The changes of the density of states due to the introduction of defects are discussed.