Berlin 2012 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 48: Focus Session: Spintronics (jointly with MA)

HL 48.5: Talk

Wednesday, March 28, 2012, 11:00–11:15, EW 201

Extended spin dephasing times in a 110-grown high-mobility GaAs/AlGaAs quantum well under conditions of optical gating measured by resonant spin amplification technique — •M. Griesbeck¹, M. Glazov², E. Sherman³, T. Korn¹, D. Schuh¹, W. Wegscheider⁴, and C. Schüller¹ — ¹Institute for Experimental and Applied Physics, Regensburg University, Germany — ²Ioffe Physical-Technical Institute, St. Petersburg, Russia — ³Department of Physical Chemistry, The University of the Basque Country, Bilbao, Spain — ⁴Solid State Physics Laboratory, ETH Zürich, Switzerland

Recently, very long spin dephasing times were discovered in a high-mobility two-dimensional electron system (2DES) embedded in a 30 nm wide symmetric (110)-grown GaAs/AlGaAs quantum well [1,2]. We have found that resonant spin amplification (RSA) [3] measurements are a convenient tool to determine all relevant parameters of anisotropic spin dynamics in our sample. Here, we show that a decrease of the carrier density by low-intensity above-barrier illumination (often referred to as optical gating) leads to a drastic increase of both the in-plane and the out-of-plane spin dephasing times. The observed spin dephasing time along the growth direction exceeds by far the previously reported values, what is most likely related to the high sample quality and the precise control of the band profile of the quantum well.

[1] R. Völkl et al., Phys. Rev. B 83, 241306 (2011)

[2] M. Griesbeck et al., preprint: http://arxiv.org/abs/1111.5438

[3] J. M. Kikkawa et al., Phys. Rev. Lett. 80, 4313 (1998)