title: Spatial structure of Mn-Mn acceptor pairs in GaAs.
abstract: The local density of states of Mn-Mn pairs in GaAs is mapped with cross-sectional scanning tunneling microscopy and compared with theoretical calculations based on envelope-function and tight-binding models. These measurements and calculations show that the crosslike shape of the Mn-acceptor wave function in GaAs persists even at very short Mn-Mn spatial separations. The resilience of the Mn-acceptor wave function to high doping levels suggests that ferromagnetism in GaMnAs is strongly influenced by impurity-band formation. The envelope-function and tight-binding models predict similarly anisotropic overlaps of the Mn wave functions for Mn-Mn pairs. This anisotropy implies differing Curie temperatures for Mn delta-doped layers grown on differently oriented substrates.
authors.affiliation: COBRA Inter-University Research Institute, Eindhoven University of Technology, P.O. Box 513, NL-5600MB Eindhoven, The Netherlands.
authors.forename: A M
authors.initials: AM
authors.lastname: Yakunin
authors.forename: A Yu
authors.initials: AY
authors.lastname: Silov
authors.forename: P M
authors.initials: PM
authors.lastname: Koenraad
authors.forename: J-M
authors.initials: JM
authors.lastname: Tang
authors.forename: M E
authors.initials: ME
authors.lastname: Flatté
authors.forename: W
authors.initials: W
authors.lastname: Van Roy
authors.forename: J
authors.initials: J
authors.lastname: De Boeck
authors.forename: J H
authors.initials: JH
authors.lastname: Wolter