Regensburg 2004 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 29: Spinabh
ängiger Transport I
HL 29.10: Vortrag
Mittwoch, 10. März 2004, 17:30–17:45, H13
ZnMnSe–Spinaligner on inverted GaAs/AlGaAs–2DEGs — •T. Leeb1, M. Döppe1, M. Reinwald1, H.-P. Tranitz1, D. Weiss1, W. Wegscheider1, P. Grabs2, G. Schmidt2, and L. Molenkamp2 — 1Institut für Experimentalphysik, Universität Regensburg, D-93040 Regensburg, Germany — 2Physikalisches Institut, Universität Würzburg, D-97074 Würzburg, Germany
The optical detection of spin injection in ZnBeMnSe/GaAs/AlGaAs–semiconductor heterostructures represents a convincing, however, indirect result of voltage driven spin transfer across a semiconductor interface. In contrast, spin injection into a two dimensional electron gas (2DEG) has not yet been clearly proven in magnetotransport experiments. We have fabricated n-doped Zn1−x−yBexMnySe–spinaligner contacts on an inverted GaAs/AlGaAs–2DEG–structure which was applied to avoid barriers along the current path. The GaAs surface preparation and the conditions of the ZnMnSe growth initiation are crucial for achieving a low barrier electronic structure at the ZnMnSe/GaAs–interface. A strong Zeeman splitting in the conduction band of the Mn–doped II–VI semiconductor is observed in photoluminescence measurements at small external magnetic fields. This verifies the spin aligning capability of the ZnMnSe contact due to a strongly reduced transmission coefficient for minority spin electrons. Magnetotransport measurements have been performed on a microstructured Hall contact geometry which was developed according to theoretical considerations concerning spin equilibration between quantum hall edge channels. This work is supported by DFG via SFB 348 and by BMBF 13N8282.