Search for Nagaoka ferromagnetism in non-magnetic doped semiconductors

• Published in: Physica. B, Condensed matter Vol. 403; no. 5; pp. 1508 - 1510
• Main Authors: Bhatt, R.N., Nielsen, E.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01.04.2008; Elsevier
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Doped semiconductors; Exact sciences and technology; Ferromagnetism; Hubbard model; Magnetic properties and materials; Magnetic semiconductors; Physics; Studies of specific magnetic materials; 71.27. + a; 75.40.Mg; Doped semiconductors; 72.20.Ee; 71.30. + h; 73.21.La; 75.50.Pp; Hubbard model; Ferromagnetism; 75.75. + a; 71.23.−k; 71.27.+a; Disordered systems; Nonmagnetic impurities; Ground states; Doping; High temperature; Magnetic semiconductors; Manganese arsenides; 71.23.-k; Impurity density; Quantum dots; Three-dimensional systems; 71.30.+h; Semimagnetic semiconductors; High spin states; Polarized spin; Spin state; 75.75.+a
• ISSN: 0921-4526; 1873-2135
• DOI: 10.1016/j.physb.2007.10.366

While ferromagnetism at relatively high temperatures is seen in diluted magnetic semiconductors such as Ga 1 - x Mn x As , under certain conditions semiconductors doped with non-magnetic impurities may also exhibit a ferromagnetic ground state. We investigate the possibility of ferromagnetism in a generalized disordered Hubbard model designed to characterize hydrogenic centers in semiconductors. We demonstrate the occurrence of high spin ground states in clusters (e.g. doped quantum dots), and discuss the nature of the single-particle states in a positionally disordered three-dimensional system with a maximally spin-polarized ground state. In particular, we identify the mobility edges, and describe their dependence on impurity density and potential.