Effect of electron-electron scattering on spin dephasing in a high-mobility low-density two-dimensional electron gas

Ruan, Xz Z.; Luo, Hongliang; Ji, Yang; Xu, Z. Y.; Umansky, V.

doi:10.1103/physrevb.77.193307

Cited by 30 publications

(67 citation statements)

References 31 publications

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“…The peak in the density dependence of the SRT has been theoretically predicted by Jiang and Wu 48 and experimentally confirmed [52][53][54][55] recently, which is attributed to the crossover from the nondegenerate to degenerate limit. The peak in the temperature dependence of the SRT was predicted by Zhou et al 23 and experimentally realized by Leyland et al, 56 Ruan et al, 57 and Han et al, 54 which is solely caused by the Coulomb scattering. 23 The location of the peak is insensitive to the gate voltage just the same as the case for electrons in (111) QWs.…”

Section: Numerical Resultsmentioning

confidence: 89%

Hole spin relaxation inp-type (111) GaAs quantum wells

Wang¹,

Wu²

2012

Phys. Rev. B

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Hole spin relaxation in p-type (111) GaAs quantum wells is investigated in the case with only the lowest hole subband, which is heavy-hole like in (111) GaAs/AlAs and light-hole like in (111) GaAs/InP quantum wells, being relevant. The subband Löwdin perturbation method is applied to obtain the effective Hamiltonian including the Dresselhaus and Rashba spin-orbit couplings. Under a proper gate voltage, the total in-plane effective magnetic field in (111) GaAs/AlAs quantum wells can be strongly suppressed in the whole momentum space, while the one in (111) GaAs/InP quantum wells can be suppressed only on a special momentum circle. The hole spin relaxation due to the D'yakonov-Perel' and Elliott-Yafet mechanisms is calculated by means of the fully microscopic kinetic spin Bloch equation approach with all the relevant scatterings explicitly included. For (111) GaAs/AlAs quantum wells, extremely long heavy-hole spin relaxation time (upto hundreds of nanoseconds) is predicted. In addition, we predict a pronounced peak in the gate-voltage dependence of the heavy-hole spin relaxation time due to the D'yakonov-Perel' mechanism. This peak origins from the suppression of the unique inhomogeneous broadening in (111) GaAs/AlAs quantum wells. Moreover, the Elliott-Yafet mechanism influences the spin relaxation only around the peak area due to the small spin mixing between the heavy and light holes in quantum wells with small well width. We also show the anisotropy of the spin relaxation. In (111) GaAs/InP quantum wells, a mild peak, similar to the case for electrons in (111) GaAs quantum wells, is also predicted in the gate-voltage dependence of the light-hole spin relaxation time. The contribution of the Elliott-Yafet mechanism is always negligible in this case.

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Section: Numerical Resultsmentioning

confidence: 89%

Hole spin relaxation inp-type (111) GaAs quantum wells

Wang¹,

Wu²

2012

Phys. Rev. B

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“…4(a) is actually the Coulomb peak in the temperature dependence, as revealed previously in other systems. [27][28][29][30][31] Here the Fermi temperature of the electrons is T F = 40 K, and the Coulomb peak is located in the range of (T F /2, T F ). With the decrease of E z , the Coulomb peak shifts towards the lower temperature regime, and finally disappears when E z approaches 82 kV/cm.…”

Section: B Temperature Dependence Of Srtmentioning

confidence: 99%

“…The peak was predicted to be close to T F in n-type high-mobility (001) GaAs quantum wells 27 while later observed experimentally at about T F /2 in n-type high-mobility (001) GaAs/GaAlAs heterostructure. 29 In p-type highmobility (001) Si/SiGe (Ge/SiGe) quantum wells, the peak was predicted to be at about T F (T F /2). 31 In intrinsic bulk GaAs, this peak was predicted to be in the range of (T F /4, T F /2).…”

Section: Introductionmentioning

confidence: 99%

“…5,8,[23][24][25] The nonmonotonic dependence of the Coulomb scattering rate 1/τ ee on temperature T during the crossover of electrons from the degenerate to nondegenerate limits [e.g., for two-dimensional electrons 1/τ ee ∝ T 2 (T −1 ) when T ≪ T F (T ≫ T F ) with T F denoting the Fermi temperature 26 ] can lead to a peak in the temperature dependence of the SRT in the strong scattering limit when the Coulomb scattering dominates. [27][28][29][30][31] This peak is called as the "Coulomb peak" in the temperature dependence. It appears around T F , with the location influenced by the temperature de- pendence of the inhomogeneous broadening and thus being sample dependent.…”

Section: Introductionmentioning

confidence: 99%

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Spin relaxation in n-type (111) GaAs quantum wells

Sun

Zhang

2010

Journal of Applied Physics

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We investigate the spin relaxation limited by the D'yakonov-Perel' mechanism in n-type (111) GaAs quantum wells, by means of the kinetic spin Bloch equation approach. In (111) GaAs quantum wells, the in-plane effective magnetic field from the D'yakonov-Perel' term can be suppressed to zero on a special momentum circle under the proper gate voltage, by the cancellation between the Dresselhaus and Rashba spin-orbit coupling terms. When the spin-polarized electrons mainly distribute around this special circle, the in-plane inhomogeneous broadening is small and the spin relaxation can be suppressed, especially for that along the growth direction of quantum well. This cancellation effect may cause a peak (the cancellation peak) in the density or temperature dependence of the spin relaxation time. In the density (temperature) dependence, the interplay between the cancellation peak and the ordinary density (Coulomb) peak leads to rich features of the density (temperature) dependence of the spin relaxation time. The effect of impurities, with its different weights on the cancellation peak and the Coulomb peak in the temperature dependence of the spin relaxation, is revealed. We also show the anisotropy of the spin relaxation with respect to the spin-polarization direction.

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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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Effect of electron-electron scattering on spin dephasing in a high-mobility low-density two-dimensional electron gas

Cited by 30 publications

References 31 publications

Hole spin relaxation inp-type (111) GaAs quantum wells

Hole spin relaxation inp-type (111) GaAs quantum wells

Spin relaxation in n-type (111) GaAs quantum wells

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

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