Spin relaxation in optically excited quantum wells

Snelling, M. J.; Plaut, A. S.; Flinn, G.P.; Tropper, A.C.; Harley, R. T.; Kerr, T. M.

doi:10.1016/0022-2313(90)90147-4

Cited by 28 publications

(16 citation statements)

References 7 publications

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“…The excitation density dependence of spin relaxation was investigated in Refs. [66,514,[606][607][608][609][610][611][612]. Interestingly, it was discovered that the spin lifetime decreases with excitation density at low temperature in n-doped quantum wells [66,608,610].…”

Section: Spin Relaxation In (001) Quantum Wellsmentioning

confidence: 97%

Spin dynamics in semiconductors

2010

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This article reviews the current status of spin dynamics in semiconductors which has achieved a lot of progress in the past years due to the fast growing field of semiconductor spintronics. The primary focus is the theoretical and experimental developments of spin relaxation and dephasing in both spin precession in time domain and spin diffusion and transport in spacial domain. A fully microscopic many-body investigation on spin dynamics based on the kinetic spin Bloch equation approach is reviewed comprehensively.Comment: a review article with 193 pages and 1103 references. To be published in Physics Reports

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Section: Spin Relaxation In (001) Quantum Wellsmentioning

confidence: 97%

Spin dynamics in semiconductors

2010

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“…This will require not only long spin-memory times but also an ability to control spin orientation or relaxation with an applied electric field, preferably at room temperature. Recent experiments on (1 1 0)-oriented III-V quantum wells (QWs) have demonstrated the existence of a predicted [1,2] dramatic increase of spin memory at room temperature but, thus far, approaches to gate control, for example based on carrier injection [3,4] or application of combined magnetic and electric fields [5], work only at low temperatures. By contrast large variation of spin relaxation rate with modest applied field has been predicted for (1 1 0)-oriented GaAs/AlGaAs QWs through the Rashba effect [6]-manipulation of the conduction band spin splitting by applied electric field-which has the possibility of room temperature operation.…”

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confidence: 99%

Gated spin relaxation in (110)-oriented quantum wells

Henini

Karimov

John

et al. 2004

Physica E: Low-dimensional Systems and Nanostructures

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“…Much work has been devoted to generating spins in semiconductors either optically [2], by injection through magnetic semiconductors [3][4][5], or within ferromagnetic semiconductors [6], while the transport of spin has also been shown to be feasible [7,8]. However, the relaxation of carrier spin is ascribed to several competing mechanisms and particularly at low temperatures has been found to vary widely between different samples [9][10][11][12][13]. One reason for this is that spin relaxation can be particularly sample dependent since it is strongly influenced by impurities and defects.…”

mentioning

confidence: 99%

“…Changes in the electron-hole overlap in the growth direction, to which BAP is sensitive, are found to be minimal within this bias regime. A theory encompassing all spin-scattering mechanisms for the whole range of extended and localized states of electrons (and excitons [13]) is necessary to explain our results.…”

mentioning

confidence: 99%

Gateable Suppression of Spin Relaxation in Semiconductors

et al. 2001

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The decay of spin memory in a 2D electron gas is found to be suppressed close to the metal-insulator transition. By dynamically probing the device using ultrafast spectroscopy, relaxation of optically excited electron spin is directly measured as a function of the carrier density. Motional narrowing favors spin preservation in the maximally scattered but nonlocalized electronic states. This implies that the spinrelaxation rate can be both tuned in situ and specifically engineered in appropriate device geometries. DOI: 10.1103/PhysRevLett.86.2150 Emerging technologies for generating and manipulating electronic spins are heralded as the precursor to a new generation of spin-functional devices [1]. One of the key requirements is to find a way to control electron spin in semiconductors which can be independently gated. Much work has been devoted to generating spins in semiconductors either optically [2], by injection through magnetic semiconductors [3][4][5], or within ferromagnetic semiconductors [6], while the transport of spin has also been shown to be feasible [7,8]. However, the relaxation of carrier spin is ascribed to several competing mechanisms and particularly at low temperatures has been found to vary widely between different samples [9][10][11][12][13]. One reason for this is that spin relaxation can be particularly sample dependent since it is strongly influenced by impurities and defects. It is therefore desirable that the same sample be used within a study. However, circumstances may prevent this, as in investigations of the dependence of spin relaxation on background doping level, where different wafers must be used [14]. In addition, such structures have no means for tuning the spin relaxation in a prescribed way.In this Letter, we show an advantageous method which avoids the use of multiple samples to vary the number of carriers in a semiconductor by applying a reverse bias to a semitransparent Schottky contact situated above a charge transport layer. The effect of the gate is to transform the quasi-2D electron gas (2DEG) from a high-density metallic state to a low-density insulating state. At low temperatures it is possible to use this technique to reduce the conductivity by several orders of magnitude. This large change in conductivity is, however, accompanied by a relatively small change in electron density, typically less than an order of magnitude. It has been realized that the remote ionized donors that provide the electrons for the 2DEG play an important role in this drop in conductivity [15][16][17]. Spatial variations in the density of these donors result in random fluctuations in the potential in the plane of the 2DEG. In the conducting regime, the 2DEG acts to screen these fluctuations. However, as the density is reduced the screening becomes less effective and the fluctuations grow. This manifests itself as electron localization and corresponds to a large decrease in conductivity. In this Letter, the spinrelaxation dynamics of photoexcited carriers are investigated as we pass through th...

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Spin relaxation in optically excited quantum wells

Cited by 28 publications

References 7 publications

Spin dynamics in semiconductors

Spin dynamics in semiconductors

Gated spin relaxation in (110)-oriented quantum wells

Gateable Suppression of Spin Relaxation in Semiconductors

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