Regensburg 2010 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 33: Poster I: Transport, including Magnetic-Field Effects
HL 33.12: Poster
Tuesday, March 23, 2010, 18:30–20:30, Poster D1
Tuning of Structure Inversion Asymmetry (SIA) by the δ-Doping Position in (001)-Grown GaAs Quantum Wells (QW) — •Vera Lechner1, Sebastian Stachel1, Peter Olbrich1, Leonid Golub2, Dieter Schuh1, Werner Wegscheider1, Vasily Belkov2, and Sergey Ganichev1 — 1Terahertz Center, University of Regensburg, Germany — 2Ioffe Institute, St. Petersburg, Russia
We demonstrate that the preparation of QWs with various δ-doping layer positions accompanied by measurements of the magnetogyrotropic photogalvanic effect (MGPE) [1] allows to grow samples with controllable SIA. The THz-laser induced MPGE in the presence of an in-plane magnetic field B measured in n-type GaAs structures originates from bulk inversion asymmetry (BIA) and SIA and therefore reflects their behaviour. We show that for a proper experimental geometry, currents measured along and perpendicular to B are proportional to BIA and SIA, respectively [2]. We studied a set of samples with fixed QW width and different δ-doping positions as well as with fixed doping position but different in the QW width. Our experiments prove that shifting the δ-doping layer from one side of the QW to the other results in a change of sign of the SIA-caused MPGE. We were able to grow structures without Rashba constant and structures with equal Rashba and Dresselhaus spin splittings. We also detected a MPGE-caused current in undoped samples via carrier generation with near-infrared light.
[1] V.V. Belkov and S.D. Ganichev, Sem. Sci. Tec. 23, 114003 (2008) [2] V. Lechner et al., Appl. Phys. Lett. 94, 242109 (2009)