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Spatial structure of Mn-Mn acceptor pairs in GaAs
Journal article   Peer reviewed

Spatial structure of Mn-Mn acceptor pairs in GaAs

A. M Yakunin, A. Yu Silov, P. M Koenraad, J. -M Tang, M. E Flatté, W Van Roy, J De Boeck and J. H Wolter
Physical review letters, Vol.95(25), 256402
12/13/2005
DOI: 10.1103/PhysRevLett.95.256402
PMID: 16384482

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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 wavefunction 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.
Physics - Materials Science

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