Phys. Rev. Lett. 95, 256402 (2005) [4 pages]Spatial Structure of Mn-Mn Acceptor Pairs in GaAsReceived 23 May 2005; published 13 December 2005 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 δ-doped layers grown on differently oriented substrates. © 2005 The American Physical Society URL:
http://link.aps.org/doi/10.1103/PhysRevLett.95.256402
DOI:
10.1103/PhysRevLett.95.256402
PACS:
71.55.Eq, 73.20.−r, 75.30.Hx, 75.50.Pp
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