Electronic Structure and Magnetic Properties of Doped GaAs (Zinc Blende) with Double Impurities and Defects

Using ab-initio calculations based on Korringa-Kohn-Rostoker coherent potential approximation (KKR-CPA) method in connection with the local density approximation (LDA), we study theoretically the electronic and magnetic properties of a system based on GaAs material. These properties have been studied, with different point defects in GaAs, which are Gallium interstitials (Gai), Gallium antisites (GaAs), Gallium vacancies (VGa), Arsenic interstitials (Asi) and Arsenic antisites (AsGa), Arsenic vacancies (VAs), and in-doped or codoped system Ga1-xCoxAs and Ga1-y-zCoyFezAs, respectively. This work presents detailed information about total and local density of states at different concentrations of these defects and doped elements; the stability of the ferromagnetic state compared with the spin-glass state has been discussed. The result of electronic properties shows that codoped GaAs material with Fe and Co become ferromagnetic, also doped GaAs with Co or Fe with a defect (hole in Ga) is stable in the ferromagnetic state. The Curie temperature is estimated from the total energy difference between the Disorder Local Moment (DLM) and the (FM) state by using a mapping on the Heisenberg model in mean field approximation.