First-principles calculations of the AsGa electronic structures

The changes in the GaAs electronic structure due to the arsenic-antisite defect have been calculated by using LDF-LMTO-ASA method to a D-2d-symmetry-supercell (Ga15As17O square(32)), which contains 15 gallium atoms, 17 arsenic atoms and 32 empty spheres. The results show that the central As-Ga atom is antibonding with its nearest neighbor arsenic atoms and therefore induces gap states in GaAs. The gap states are composed of A(1)-like state and T-2-like state. The bonding properties of gap states have been analyzed in detail by using density of states (DOS) and combined coefficients of wavefunctions. Our results of E-A1 = E-v + 0.70 eV and E-T2 = E-A1 + 1.07 eV are in good agreement with experiments as well as previous calculation results obtained by other self-consistent methods.