High temperature electron spin relaxation in bulk GaAs

Oertel, S.; Hübner, Jens; Oestreich, M.

doi:10.1063/1.2993344

Cited by 56 publications

(64 citation statements)

References 22 publications

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“…On the other hand, during electrical spin injection, an issue is unavoidably involved: to what degree such spin ensemble can conserve its polarization after it relaxes into a quantum well channel from an initial state of high kinetic energy. Recently an energy dependence of D'yakonov-Perel (DP) spin relaxation rate on 3 k E was testified in the motional narrowing regime [4]. It is well known that spin excitation with high kinetic energy is not in favor of accumulating a highly spin polarized ensemble in quantum well (QW) channel.…”

Section: Introductionmentioning

confidence: 99%

Dynamics of dense spin ensemble excited in a barrier layer and detected in a well

Sui

Wang

Zhu

et al. 2011

Sci. China Phys. Mech. Astron.

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Photoluminescence (PL) polarization of a spin ensemble was examined over a wide excitation wavelength range from 520 nm to 700 nm and a temperature range from 3.5 K to 300 K after it transfers from a (AlGa)As barrier layer and eventually quenches irradiatively in a GaAs quantum well (QW). A highest PL circular polarization of 30% can be kept at temperatures up to 120 K, while its room temperature value reaches about 17%. It is found that the main features of the optical spin orientation in bulk Al 0.27 Ga 0.73 As materials can be reproduced in terms of the wavelength dependence of PL polarization degree, as the spin polarized ensemble transfers and relaxes into GaAs QW. The transient of PL polarization degree also indicates that a dense spin ensemble collected from the barrier region is in favor of conserving its polarization in GaAs QW as evidenced by a rising temporal response. spin polarized transport, optical orientation, dense spin relaxation, quantum well PACS: 72.25.Dc, 72.25.Fe, 73.40.Kp

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Section: Introductionmentioning

confidence: 99%

Dynamics of dense spin ensemble excited in a barrier layer and detected in a well

Sui

Wang

Zhu

et al. 2011

Sci. China Phys. Mech. Astron.

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“…We note that our results are consistent with a recent study where electron-spin-relaxation time in bulk GaAs at room temperature was found to increase linearly with carrier density when the D'yakonovPerel' mechanism dominates. 57 With the inhomogeneous spin-relaxation time, the spatiotemporal evolution of a spin-polarized packet was evaluated using Eq. ͑11͒ with parameters similar to those used in Fig.…”

Section: Inhomogeneous Spin Relaxationmentioning

confidence: 99%

Ambipolar spin diffusion and D'yakonov-Perel' spin relaxation in GaAs quantum wells

2009

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We report theoretical and experimental studies of ambipolar spin diffusion in a semiconductor. A circularly polarized laser pulse is used to excite spin-polarized carriers in a GaAs multiple quantum-well sample at 80 K. Diffusion of electron and spin densities is simultaneously measured using a spatially and temporally resolved pump-probe technique. Two regimes of diffusion for spin-polarized electrons are observed. Initially, the rate of spin diffusion is similar to that of density diffusion and is controlled by the ambipolar diffusion coefficient. At later times, the spin diffusion slows down considerably relative to the density diffusion and appears to be controlled by a nonconstant ͑decreasing͒ spin-diffusion coefficient. We suggest that the long-time behavior of the spin density can be understood in terms of an inhomogeneous spin-relaxation rate, which grows with decreasing density. The behavior of the spin-relaxation rate is consistent with a model of D'yakonov-Perel' relaxation limited by the Coulomb scattering between carriers.

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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%

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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High temperature electron spin relaxation in bulk GaAs

Cited by 56 publications

References 22 publications

Dynamics of dense spin ensemble excited in a barrier layer and detected in a well

Dynamics of dense spin ensemble excited in a barrier layer and detected in a well

Ambipolar spin diffusion and D'yakonov-Perel' spin relaxation in GaAs quantum wells

Hole spin relaxation in intrinsic andp-type bulk GaAs

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