Berlin 2008 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 26: III-V semiconductors I

HL 26.5: Vortrag

Dienstag, 26. Februar 2008, 16:45–17:00, EW 202

Mn modulation-doped two-dimensional hole systems — •Ursula Wurstbauer, Matthias Habl, Dieter Schuh, and Werner Wegscheider — Institut für Experimentelle und Angewandte Physik, Universität Regensburg

In order to study the interplay of localized magnetic ions with low-dimensional charge carrier systems, we have fabricated Mn modulation-doped two-dimensional hole gases in the InGaAs/InAs material system and report on magnetotransport measurements herein. For preparation of such systems, we grow shallow single InAs quantum well (QW) structures on a strain relaxed buffer on GaAs substrates by molecular beam epitaxy. Our investigations are focused on the dependence on the doping density and the symmetry of the QW structures. Magnetotransport measurements at low temperatures exhibit pronounced SdH-oscillations in the longitudinal resistance and well developed Hall-plateaus in the Hall-resistance. Furthermore, the temperature dependent sheet resistivity increases dramatically at lower temperatures, indicating a strongly localized system for both, the inverted and double sided doped QW structures. These structures show in the mK region below a critical magnetic field insulating and hysteretic behaviour. Additional jumps in the resistance can be observed, indicating ferromagnetic interaction between the holes in the two-dimensional hole system and the magnetic moments of the Mn²⁺ ions.