The changes in the GaAs electronic structure due to the arsenic-antisite defect have been calculated by using LDF-LMTO-ASA method to a D2d-symmetry-supercell ( Ga15As17□32)c,o ntains 15 gallium atoms, 17 arsenic atoms and 32 empty spheres. The results show that the central AsGa atom is antibonding with its nearest neighbor arsenic atoms and therefore induces gap states in GaAs. The gap states are composed of A1-like state and T2-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 EA1 =Ev+0.70 eV and= ET2+1.07eV are in good agreement with experiments as well as previous calculation results obtained by other self-consistent methods.
Key words
arsenic-antisite /
electronic structure /
gap state
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