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Oscillatory Dyakonov-Perel spin dynamics in two-dimensional electron gases

Oscillatory Dyakonov-Perel spin dynamics in two-dimensional electron gases
Oscillatory Dyakonov-Perel spin dynamics in two-dimensional electron gases
Optical pump-probe measurements of spin dynamics at temperatures down to 1.5 K are described for a series of (001)-oriented GaAs/AlGaAs quantum well samples containing high mobility two-dimensional electron gases (2DEGs). For well widths ranging from 5 to 20 nm and 2DEG sheet densities from 1.75×1011 to 3.5×1011 cm-2, the evolution of a small injected spin population is found to be a damped oscillation rather than an exponential relaxation, consistent with the quasi-collision-free regime of the Dyakonov-Perel spin dynamics. A Monte Carlo simulation method is used to extract the spin-orbit-induced electron spin precession frequency |Ω(kF)| and electron momentum scattering time τp* at the Fermi wave vector. The spin decay time passes through a minimum at a temperature corresponding to the transition from collision-free to collision-dominated regimes and τp* is found to be close to the ensemble momentum scattering time tp obtained from Hall measurements of electron mobility. The values of |Ω(kF)| give the Dresselhaus or bulk inversion asymmetry (BIA) coefficient of spin-orbit interaction as a function of electron confinement energy in the quantum wells and show, qualitatively, the behavior expected from k·p theory.
1550-235X
Leyland, W.J.H.
e6a7d9aa-be90-41ef-90db-bc411363b84b
Harley, R.T.
54613031-f60f-45f4-9b20-e49bcfd53b77
Henini, M.
dffaac17-caab-4a18-9eb6-c858d8bb1ed2
Shields, A.J.
2d016dc0-78a3-4368-9f54-49b00f381a2d
Farrer, I.
8e39904e-2255-4432-be5b-1b46c5b0dd9a
Ritchie, D.A.
83562b7e-0986-4822-9cfe-8c4ac95596c7
Leyland, W.J.H.
e6a7d9aa-be90-41ef-90db-bc411363b84b
Harley, R.T.
54613031-f60f-45f4-9b20-e49bcfd53b77
Henini, M.
dffaac17-caab-4a18-9eb6-c858d8bb1ed2
Shields, A.J.
2d016dc0-78a3-4368-9f54-49b00f381a2d
Farrer, I.
8e39904e-2255-4432-be5b-1b46c5b0dd9a
Ritchie, D.A.
83562b7e-0986-4822-9cfe-8c4ac95596c7

Leyland, W.J.H., Harley, R.T., Henini, M., Shields, A.J., Farrer, I. and Ritchie, D.A. (2007) Oscillatory Dyakonov-Perel spin dynamics in two-dimensional electron gases. Physical Review B, 76 (19), [195305]. (doi:10.1103/PhysRevB.76.195305).

Record type: Article

Abstract

Optical pump-probe measurements of spin dynamics at temperatures down to 1.5 K are described for a series of (001)-oriented GaAs/AlGaAs quantum well samples containing high mobility two-dimensional electron gases (2DEGs). For well widths ranging from 5 to 20 nm and 2DEG sheet densities from 1.75×1011 to 3.5×1011 cm-2, the evolution of a small injected spin population is found to be a damped oscillation rather than an exponential relaxation, consistent with the quasi-collision-free regime of the Dyakonov-Perel spin dynamics. A Monte Carlo simulation method is used to extract the spin-orbit-induced electron spin precession frequency |Ω(kF)| and electron momentum scattering time τp* at the Fermi wave vector. The spin decay time passes through a minimum at a temperature corresponding to the transition from collision-free to collision-dominated regimes and τp* is found to be close to the ensemble momentum scattering time tp obtained from Hall measurements of electron mobility. The values of |Ω(kF)| give the Dresselhaus or bulk inversion asymmetry (BIA) coefficient of spin-orbit interaction as a function of electron confinement energy in the quantum wells and show, qualitatively, the behavior expected from k·p theory.

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More information

Published date: November 2007
Organisations: Quantum, Light & Matter Group

Identifiers

Local EPrints ID: 64273
URI: http://eprints.soton.ac.uk/id/eprint/64273
ISSN: 1550-235X
PURE UUID: 80a8ff61-cefb-4846-adda-273e35d28cb9

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Date deposited: 13 Jan 2009
Last modified: 15 Mar 2024 11:47

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Contributors

Author: W.J.H. Leyland
Author: R.T. Harley
Author: M. Henini
Author: A.J. Shields
Author: I. Farrer
Author: D.A. Ritchie

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