Magnetic properties of 3d impurities in GaAs

• Published in: Journal of magnetism and magnetic materials 2007-03, Vol.310 (2), p.2120-2122
• Main Authors: Baykov, V.I., Korzhavyi, P.A., Smirnova, E.A., Abrikosov, I.A., Johansson, B.
• Format: Article
• Language: English
• Subjects: Ab initio calculation; Magnetic semiconductor; NATURAL SCIENCES; NATURVETENSKAP; Spintronic; TECHNOLOGY; TEKNIKVETENSKAP
• ISSN: 0304-8853; 1873-4766
• DOI: 10.1016/j.jmmm.2006.10.791

Electronic structure, thermodynamic, and magnetic properties of 3d-transition metal (TM) impurities in GaAs have been studied from first principles using Green's function approach. The studied TM impurities (V, Cr, Mn, and Fe) are found to form substitutional alloys on the Ga sublattice. The possibility of raising the Curie temperature T C in (GaMn)As by co-doping it with Cr impurities was examined on the basis of total energy difference between the disordered local moment (DLM) and the ferromagnetically ordered (FM) spin configurations. The calculated Curie temperature and magnetic moment have maxima for GaAs doped with Cr and Mn. The magnetic properties of Mn-doped GaAs are shown to be more sensitive to antisite As defects than those of Cr-doped GaAs. However, the Cr impurities are sensitive to the presence of acceptor defects, such as vacancies on the Ga sublattice. The investigation of the electronic structure of pseudo-ternary alloys (Ga (1− x − y )Mn x Cr y )As has shown a mutual compensation of Mn and Cr impurities. Therefore, in order to reach the highest critical temperature, GaAs has to be separately doped with Cr or Mn impurities. The GaAs doped with Fe is found to be non-ferromagnetic.