title: Role of embedded clustering in dilute magnetic semiconductors: Cr doped GaN.
abstract: Results of extensive density-functional studies provide direct evidence that Cr atoms in Cr:GaN have a strong tendency to form embedded clusters, occupying Ga sites. Significantly, for larger than 2-Cr-atom clusters, states containing antiferromagnetic coupling with net spin in the range 0.06-1.47 muB/Cr are favored. We propose a picture where various configurations coexist and the statistical distribution and associated magnetism will depend sensitively on the growth details. Such a view may elucidate many puzzling observations related to the structural and magnetic properties of III-N and other dilute semiconductors.
authors.affiliation: School of Physics, The University of Sydney, Sydney 2006, New South Wales, Australia.
authors.forename: X Y
authors.initials: XY
authors.lastname: Cui
authors.forename: J E
authors.initials: JE
authors.lastname: Medvedeva
authors.forename: B
authors.initials: B
authors.lastname: Delley
authors.forename: A J
authors.initials: AJ
authors.lastname: Freeman
authors.forename: N
authors.initials: N
authors.lastname: Newman
authors.forename: C
authors.initials: C
authors.lastname: Stampfl