Regensburg 2007 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 20: Magnetic Thin Films II
MA 20.6: Vortrag
Mittwoch, 28. März 2007, 16:30–16:45, H5
Investigation of the crystallographic structure of hydrogenated (Ga,Mn)As — •Christoph Bihler1, Hans Huebl1, Bastian Galler1, Martin Brandt1, Gema Martinez-Criado2, Gianluca Ciatto2, Aldo Amore Bonapasta3, Francesco Filippone3, Wladimir Schoch4, and Wolfgang Limmer4 — 1Walter Schottky Institut, TU München, Am Coulombwall 3, 85748 Garching — 2ESRF, 6 rue J. Horowitz, Boite Postale 220, 38043 Grenoble, France — 3ISM, Via Salaria, CP 10, 00016 Monterotondo Stazione, Italy — 4Institut für Halbleiterphysik, Universität Ulm, 89069 Ulm
The lattice expansion of (Ga,Mn)As samples after deuteration Δ VD/VMn−As≈0.14 obtained from x-ray diffraction (XRD) agrees best with that expected for a complex with the D atom bond-centered (BC) between the Mn and a neighboring As atom, but the difference to the volume expansion expected for the antibonding (AB) configuration is too small to draw unambiguous conclusions. However, the absence of a second peak or shoulder in the Fourier transform of the Mn K-edge extended x-ray absorption fine structure (EXAFS) χ function corresponding to the first coordination shell of deuterated samples, as well as the comparison of the corresponding x-ray absorption near-edge structure (XANES) with simulations of the different complexes strongly suggests that the BC complex predicted by theoretical calculations can be excluded in the deuterated samples. Rather, both EXAFS and XANES spectra can be explained by the formation of AB complexes or complexes in which the D atom is not bound to a nearest As neighbor, but a more distant As atom.