ab initio study of magnetism in III-V and II-VI-based diluted magnetic semiconductors

摘要

Electronic structure and magnetic properties of Ga{sub}(1-x)Mn{sub}xAs, Ga{sub}(1-x)Mn{sub}xN, Zn{sub}(1-x)M{sub}xO and ZnZn{sub}(1-x)M{sub}xTe(M=V, Cr, Mn, Fe, and Co) diluted magnetic semiconductors (DMS) are calculated by the tight-binding LMTO method in the 64-atom supercell. Calculations are made at several N with varied spatial distribution of dopant atoms and codoping of DMSs. The results show that stability of the ferro- and antiferromagnetic (FM and AFM) states in DMSs strongly correlates with the occupation and energy position of 3d-dopant bands. Adequacy of the double exchange and superexchange mechanisms for explanation of the FM vs. AFM competition is discussed.