Dependence of spin dephasing on initial spin polarization in a high-mobility two-dimensional electron system

Stich, Dominik; Zhou, Jun; Korn, Tobias; Schulz, Robert; Schuh, Dieter; Wegscheider, Werner; Wu, M. W.; Schüller, Christian

doi:10.1103/physrevb.76.205301

Cited by 54 publications

(96 citation statements)

References 27 publications

(44 reference statements)

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“…8 A similar anisotropy of the spin dephasing arises in [001]-grown structures for equal strength of Rashba and Dresselhaus fields. [9][10][11][12][13] For such structures, however, the suppression of the DP mechanism occurs along one in-plane crystallographic orientation. While all-electrical devices are envisioned for most future semiconductor spintronics applications, optical spectroscopy techniques have proven to be very useful for the study of spin dynamics in direct-gap semiconductor heterostructures, and a variety of techniques, including time-resolved Faraday rotation (TRFR), 14 Hanle measurements, and spin noise spectroscopy (SNS) 15 have been developed.…”

Section: Introductionmentioning

confidence: 99%

Strongly anisotropic spin relaxation revealed by resonant spin amplification in (110) GaAs quantum wells

et al. 2012

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We have studied spin dephasing in a high-mobility two-dimensional electron system confined in a GaAs/AlGaAs quantum well grown in the [110] direction, using the resonant spin amplification (RSA) technique. From the characteristic shape of the RSA spectra, we are able to extract the spin dephasing times (SDTs) for electron spins aligned along the growth direction or within the sample plane, as well as the g factor. We observe a strong anisotropy in the spin dephasing times. While the in-plane SDT remains almost constant as the temperature is varied between 4 and 50 K, the out-of-plane SDT shows a dramatic increase at a temperature of about 25 K and reaches values of about 100 ns. The SDTs at 4 K can be further increased by additional, weak above-barrier illumination. The origin of this unexpected behavior is discussed. The SDT enhancement is attributed to the redistribution of charge carriers between the electron gas and remote donors.

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Section: Introductionmentioning

confidence: 99%

Strongly anisotropic spin relaxation revealed by resonant spin amplification in (110) GaAs quantum wells

et al. 2012

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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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“…11, 14,15,[18][19][20][21][22][24][25][26][27] For (110) symmetric QWs, the effective magnetic field due to the Dresselhaus term is oriented along the growth direction, which leads to an absent DP relaxation for electron spins along this direction. 29,33,34 Recently, some attention has been devoted to (111) QWs where electron spin relaxation also shows rich properties.…”

Section: Introductionmentioning

confidence: 99%

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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Dependence of spin dephasing on initial spin polarization in a high-mobility two-dimensional electron system

Cited by 54 publications

References 27 publications

Strongly anisotropic spin relaxation revealed by resonant spin amplification in (110) GaAs quantum wells

Strongly anisotropic spin relaxation revealed by resonant spin amplification in (110) GaAs quantum wells

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

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

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