Density dependence of spin relaxation in GaAs quantum well at room temperature

Teng, Lihua; Zhang, Peng; Lai, Tianshu; Wu, M. W.

doi:10.1209/0295-5075/84/27006

Cited by 27 publications

(39 citation statements)

References 40 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: 99%

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: 99%

Spin dynamics in semiconductors

2010

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“…Previously, the KSBE approach has been applied to study the spin dynamics in semiconductor and its nanostructures where good agreements with experiments have been achieved and many predictions have been confirmed by experiments. 30,31,32,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49 In this work, we apply the KSBE approach to both n-and p-type paramagnetic Ga(Mn)As quantum wells to study the electron spin relaxation. We distinguish the dominant spin relaxation mechanisms in different regimes and our results are consistent with the recent experimental findings.…”

Section: Introductionmentioning

confidence: 99%

Electron spin relaxation in paramagnetic Ga(Mn)As quantum wells

et al. 2009

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Electron spin relaxation in paramagnetic Ga(Mn)As quantum wells is studied via the fully microscopic kinetic spin Bloch equation approach where all the scatterings, such as the electron-impurity, electron-phonon, electron-electron Coulomb, electron-hole Coulomb, electron-hole exchange (the Bir-Aronov-Pikus mechanism) and the s-d exchange scatterings, are explicitly included. The ElliotYafet mechanism is also incorporated. From this approach, we study the spin relaxation in both n-type and p-type Ga(Mn)As quantum wells. For n-type Ga(Mn)As quantum wells where most Mn ions take the interstitial positions, we find that the spin relaxation is always dominated by the DP mechanism in the metallic region. Interestingly, the Mn concentration dependence of the spin relaxation time is nonmonotonic and exhibits a peak. This is due to the fact that the momentum scattering and the inhomogeneous broadening have different density dependences in the non-degenerate and degenerate regimes. For p-type Ga(Mn)As quantum wells, we find that the Mn concentration dependence of the spin relaxation time is also nonmonotonic and shows a peak. Differently, the cause of this behaviour is that the s-d exchange scattering (or the Bir-Aronov-Pikus) mechanism dominates the spin relaxation in the high Mn concentration regime at low (or high) temperature, whereas the DP mechanism determines the spin relaxation in the low Mn concentration regime. The Elliot-Yafet mechanism also contributes to the spin relaxation at intermediate temperatures. The spin relaxation time due to the DP mechanism increases with increasing Mn concentration due to motional narrowing, whereas those due to the spin-flip mechanisms decrease with it, which thus leads to the formation of the peak. The temperature, photo-excitation density and magnetic field dependences of the spin relaxation time in p-type Ga(Mn)As quantum wells are investigated systematically with the underlying physics revealed. Our results are consistent with the recent experimental findings.

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“…[3][4][5][6][7] In bulk materials, the spin relaxation and/or dephasing properties of the electrons and the underlying physics have been well understood after a long-time research. [8][9][10][11][12][13][14][15][16][17] However, the study on hole spin dynamics, which occurs on the time scale of the momentum scattering time (usually < 1 ps), is fairly rare, partly because of the limited resolution on the detection of such an ultrafast process. To our best knowledge, the hole spin lifetime in bulk semiconductors was only measured in intrinsic GaAs at room temperature, which evaluated the spin relaxation time of the heavy hole (∼ 110 fs).…”

Section: Introductionmentioning

confidence: 99%

“…(11) and (12). 41 For the numerical treatment of the scattering term, we take the isotropic energy spectrum from the effective-mass approximation,…”

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Hole spin relaxation in intrinsic andp-type bulk GaAs

Shen

2010

Phys. Rev. B

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We investigate hole spin relaxation in intrinsic and p-type bulk GaAs from a fully microscopic kinetic spin Bloch equation approach. In contrast to the previous study on hole spin dynamics, we explicitly include the intraband coherence and the nonpolar hole-optical-phonon interaction, both of which are demonstrated to be of great importance to the hole spin relaxation. The relative contributions of the D'yakonov-Perel' and Elliott-Yafet mechanisms on hole spin relaxation are also analyzed. In our calculation, the screening constant, playing an important role in the hole spin relaxation, is treated with the random phase approximation. In intrinsic GaAs, our result shows good agreement with the experiment data at room temperature, where the hole spin relaxation is demonstrated to be dominated by the Elliott-Yafet mechanism. We also find that the hole spin relaxation strongly depends on the temperature and predict a valley in the density dependence of the hole spin relaxation time at low temperature due to the hole-electron scattering. In p-type GaAs, we predict a peak in the spin relaxation time against the hole density at low temperature, which originates from the distinct behaviors of the screening in the degenerate and nondegenerate regimes. The competition between the screening and the momentum exchange during scattering events can also lead to a valley in the density dependence of the hole spin relaxation time in the low density regime. At high temperature, the effect of the screening is suppressed due to the small screening constant. Moreover, we predict a nonmonotonic dependence of the hole spin relaxation time on temperature associated with the screening together with the hole-phonon scattering. Finally, we find that the D'yakonov-Perel' mechanism can markedly contribute to the hole spin relaxation in the low density case at moderate temperature and in the high density case at low temperature, where the Elliott-Yafet mechanism is suppressed due to the relatively weak scattering.

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Density dependence of spin relaxation in GaAs quantum well at room temperature

Cited by 27 publications

References 40 publications

Spin dynamics in semiconductors

Spin dynamics in semiconductors

Electron spin relaxation in paramagnetic Ga(Mn)As quantum wells

Hole spin relaxation in intrinsic andp-type bulk GaAs

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