Regensburg 2013 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 102: Quantum dots and wires: Transport
HL 102.4: Talk
Friday, March 15, 2013, 12:00–12:15, H13
Magnetization of modulation-doped quantum dots prepared from InP/InGaAs heterostructures — •Florian Herzog1, Benedikt Rupprecht1, Susanne Goerke1, Marc Wilde1, Thomas Schäpers2, Hilde Hardtdegen2, Sebastian Heedt2, Christian Heyn3, and Dirk Grundler1 — 1Physik.-Dep. E10, TU München, D-85748 Garching — 2Peter Grünberg Institute (PGI-9), FZ Jülich, D-52425 Jülich — 3Institute of Applied Physics, University of Hamburg, D-20355 Hamburg
High-mobility 2D electron systems (2DESs) formed in modulation-doped InP/InGaAs heterostructures exhibit strong spin-orbit coupling due to both Rashba and Dresselhaus effects. We etched arrays of mesoscopic (diameter d=3 µm) and nanoscopic dots (d=400 nm) out of 2DESs to study the effect of lateral confinement on spin-orbit coupling. On such samples, we performed highly sensitive torque magnetometry at a few 100 mK. We report de Haas-van Alphen oscillations in the magnetization for both mesoscopic and nanoscopic dots observed up to a filling factor of ν=28. Electron densities are found to be as large as for the unpatterned 2DESs, but oscillation amplitudes are drastically smaller. We attribute this to a depletion region at the dot borders. Financial support by the DFG via the priority program “SPP 1285 - semiconductor spintronics” and NIM is gratefully acknowledged.