Spin dephasing and photoinduced spin diffusion in high-mobility 110-grown GaAs-AlGaAs two-dimensional electron systems
Spin dephasing and photoinduced spin diffusion in high-mobility 110-grown GaAs-AlGaAs two-dimensional electron systems
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高迁移率 110 生长的 GaAs-AlGaAs 二维电子系统中的自旋相移和光致自旋扩散
DOI：
10.1103/physrevb.83.241306
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
T. Korn
中科院分区：
文献类型：
--
作者：
R. Völkl;M. Griesbeck;S.A. Tarasenko;D. Schuh;W. Wegscheider;C. Schüller;T. Korn
我们通过双束Hanle实验研究了高迁移率二维电子系统中的自旋消相和自旋扩散，该系统嵌入在GaAs/AlGaAs量子阱中[110]方向生长。在极低的激发密度下，我们观察到自旋寿命大于16 ns，随着泵浦强度的增加，自旋寿命迅速降低。两个机制有助于这种减少：光激发产生空穴，空穴通过birr - aronov - pikus机制导致电子自旋衰减和自旋极化电子的复合。通过扫描泵浦和探测光束之间的距离，我们观察到自旋极化电子在超过20m的范围内的扩散。在高泵浦强度下，由于光生空穴的影响减小，在距离泵浦光束数微米处的自旋极化比在泵浦点处的极化要大。
We have studied spin dephasing and spin diffusion in a high-mobility two-dimensional electron system, embedded in a GaAs/AlGaAs quantum well grown in the [110] direction, by a two-beam Hanle experiment. For very low excitation density, we observe spin lifetimes of more than 16 ns, which rapidly decrease as the pump intensity is increased. Two mechanisms contribute to this decrease: The optical excitation produces holes, which lead to a decay of electron spin via the Bir-Aronov-Pikus mechanism and recombination with spin-polarized electrons. By scanning the distance between the pump and probe beams, we observe the diffusion of spin-polarized electrons over more than 20m. For high pump intensity, the spin polarization in a distance of several micrometers from the pump beam is larger than at the pump spot, due to the reduced influence of photogenerated holes.