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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·J. H. Wolter
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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 $δ$-doped layers grown on differently oriented substrates.

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A. M. Yakunin, A. Yu. Silov, P. M. Koenraad, J. -M. Tang, M. E. Flatté, W. Van Roy, J. De Boeck, J. H. Wolter. 2005-05-24. Spatial structure of Mn-Mn acceptor pairs in GaAs. https://doi.org/10.1103/physrevlett.95.256402

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