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O: Fachverband Oberflächenphysik

O 71: Electronic Structure of Surfaces I

O 71.7: Vortrag

Mittwoch, 18. März 2020, 16:45–17:00, REC C 213

Hard X-ray Valence-Band Mapping and Photoelectron Diffraction on InGaMnAs Thin Films — •K. Medjanik¹, A. Winkelmann², O. Yastrubchak³, J. Sadowski^4,5, L. Gluba^6,7, D. Vasilyev¹, S. Babenkov¹, S. Chernov¹, O. Fedchenko¹, H.J. Elmers¹, and G. Schönhense¹ — ¹JGU, Inst. für Physik, Mainz — ²AGH Univ. of Science and Technology, Krakow, Poland — ³Inst. of Semiconductor Physics, Kyiv, Ukraine — ⁴Inst. of Physics, Warszawa, Poland — ⁵Linnaeus Univ., Kalmar, Sweden — ⁶Inst. of Agrophysics, Lublin, Poland — ⁷Inst. of Physics, Lublin, Poland

The interplay of electronic and geometric structure is one of the key issues of materials research. We present results for the prototypical ferromagnetic semiconductor InGaMnAs (3% In, 2.5% and 5% Mn), recorded at photon energies between 3 and 5 keV at the new beamline P22 at PETRA III (Hamburg) by Time-of-Flight Momentum Microscopy [1]. In the non-centrosymmetric GaAs crystal structure, element-specific hXPD clearly reveals site-specific Ga and As diffraction patterns which are rotated by 90° at identical kinetic energies. The Mn-atoms show diffractograms, which are characteristic for the Ga-sites, as expected for substitutional Mn in GaAs [2]. Sharp valence-band k-patterns show that with increasing Mn-doping the splitting of the p1/2-derived band from the heavy- and light-hole p3/2-bands increases. In addition, the Fermi energy decreases i.e. with increased Mn content the frontier bands are less filled.

[1] K. Medjanik et al., J. of Synchr. Radiation 26, 1996 (2019). [2] T. Dietl & H. Ohno, Rev. Mod. Phys. 86, 187 (2014).