Regensburg 2010 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 52: Heterostructures
HL 52.4: Vortrag
Donnerstag, 25. März 2010, 10:45–11:00, H17
Extraordinary metastabilities in a magnetic two-dimensional hole systems — •Ursula Wurstbauer1,2, Cesary Śliwa3, Dieter Weiss2, Wolfgang Hansen1, Tomasz Dietl3, and Werner Wegscheider2,4 — 1Institute of Applied Physics, University of Hamburg, Germany — 2Institute of Experimental and Applied Physics, University of Regensburg, Germany — 3Institute of Physics, Polish Academy of Sciences, Poland — 4Solid State Physics Laboratory, ETH Zurich, Switzerland
Magnetotransport experiments on inverted manganese modulation doped compressively strained InAs quantum well structures reveal strong localization effects in coexistence with typical quantized transport phenomena in a two-dimensional charge carrier system. Here, manganese plays a dual role: it acts as an acceptor and additionally provides a localized spin of 5/2. Peculiarities of the MBE growth lead to a broadening of the doping layer resulting in a certain amount of Mn inside the channel hosting the two-dimensional holes. This phenomenon causes a hysteretic magnetic field driven metal to insulator transition with abrupt resistance changes over several orders of magnitude. The novel metastable insulator phase is a non-polarized state and originates from a large magnetic anisotropy of the heavy holes, coupled to the parent Mn acceptors by strong p-d exchange interaction. As a result, the spin relaxation of individual bound holes is remarkably enhanced and exceeds several hundreds of seconds. The influences on field-induced delocalization and extended relaxation of the holes will be discussed.