Interstitial Mn in (Ga,Mn)As: Hybridization with Conduction Band and Electron Mediated Exchange Coupling

J. Mašeka, J. Kudrnovskýa, F. Mácaa and T. Jungwirth b,c a Institute of Physics v.v.i., AS CR, Na Slovance 2, 182 21 Prague 8, Czech Republic b Institute of Physics v.v.i., AS CR, Cukrovarnická 10, 162 53 Prague 6, Czech Republic c School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD, UK

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Received: 9 06 2007;

We investigate theoretically the possibility of n-type DMS based on III-V materials with Mn impurities in interstitial instead of substitutional positions, and discuss some situations when this can happen. We show that the d-states at interstitial Mn atoms in (Ga,Mn)As hybridize with both valence and conduction bands. The hybridization is strong enough to establish an indirect ferromagnetic coupling of the Mn magnetic moments mediated either by holes or by conduction electrons. Moreover, the Curie temperatures estimated within the mean-field theory are comparable with Tc obtained for conventional materials with the same concentration of MnGa.

DOI: 10.12693/APhysPolA.112.215 PACS numbers: 71.15.Ap, 71.20.Nr, 75.50.Pp