Regensburg 2013 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 5: Spintronics: mainly interfaces and heterostructures
HL 5.9: Vortrag
Montag, 11. März 2013, 11:30–11:45, H16
Low Temperature Spin Relaxation Rate Anisotropy in (001) GaAs/AlGaAs Quantum Wells — •David English1, Peter Eldridge1, Richard Harley2, Roland Winkler3, Jens Hübner1, and Michael Oestreich1 — 1Institute for Solid State Physics, Leibniz University Hannover, Appelstr. 2, 30167 Hannover, Germany — 2School of Physics and Astronomy, University of Southampton, Southampton, SO17 1BJ, UK — 3Department of Physics, Northern Illinois University, DeKalb, IL 60115, USA
We present measurements of the appearance of an unexpected spin relaxation rate anisotropy below a temperature of 80K in (001) GaAs/AlGaAs quantum wells with asymmetric barriers. We develop a theoretical model that reveals the origin of this anisotropy.
In general, in-plane anisotropy of the spin relaxation rate is produced by interference of the bulk inversion asymmetry (BIA) term in the spin-orbit field with the structural inversion asymmetry (SIA) term [1]. Quantum wells with asymmetric barrier growth lack an SIA term due to the isomorphous nature of the bands [2]. The new theoretical model accounts for the temperature dependent filling of k-space by the conduction electrons away from k = 0. By considering higher order k states we demonstrate that the relaxation rate can be anisotropic at low temperatures, requiring only a BIA term and an asymmetric conduction electron wavefunction.
[1] N. Averkiev and L. Golub, Physical Review B 60, 15582 (1999).
[2] P. Eldridge, et al. Physical Review B 82, 045317 (2010).