Berlin 2005 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 3: Spintronik I
HL 3.6: Vortrag
Freitag, 4. März 2005, 12:00–12:15, TU P164
Properties of a nondispersive Mn-3d band in (GaxMn1−x)As — •J. Henk, A. Ernst, L. M. Sandratskii, M. Bouhassoune, and P. Bruno — MPI für Mikrostrukturphysik, Halle/S., Germany
The magnetic properties of Mn-based diluted magnetic semiconductors (DMS) depend significantly on the energy position of the Mn-3d levels. Recent photoemission experiments [1] reported on a nondispersive band at 0.3 eV binding energy in (GaxMn1−x)As which was attributed to Mn impurities. The combination of low dispersion and small Mn-3d contribution makes the nature of this band puzzling. Hence, first-principles KKR-CPA calculations were performed for both Mn substituting Ga and for Mn in the interstitial in various magnetic configurations. A nondispersive band with the experimental binding energy shows up in the Mn-interstitial case, but does not in the pure substitutional alloy. It has Mn-3d character, and its low experimental intensity is explained by its low spectral weight. Further, its occurrence is robust against various magnetic configurations of the substitutional and the interstitial Mn atoms.
[1] J. Okabayashi, A. Kimura, O. Rader, T. Mizokawa, A. Fujimori, T. Hayashi, and M. Tanaka, Phys. Rev. B 64 (2001) 125304.