Observation of the optical spin Hall effect
Observation of the optical spin Hall effect
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DOI：
10.1038/nphys676
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发表时间：
2007-09-01
期刊：
影响因子：
19.6
通讯作者：
Bramati, A.
中科院分区：
文献类型：
--
作者：
Leyder, C.;Romanelli, M.;Bramati, A.
自旋霍尔效应由垂直于电荷电流流动的自旋电流的产生组成。在Dyakonov和Perel '（1）预测35年后，它成为实验和理论研究的焦点，并构成了自旋电子学最显着的效应之一。由于电子气体中的散射和退相，很难观察到，并且仅在几年前首次得到证实（2-5）。最近，我们中的三个人预测了光学自旋霍尔效应（6），它由半导体微腔中激光产生的自旋极化激子-极化激元在真实的空间和动量空间中的分离组成（7）。这种分离是由于激子-极化激元的结构无序的弹性散射和极化激元态的极化分裂产生的有效磁场共同作用的结果。激子自旋电流由激光泵浦的线性偏振控制。在这里，我们报告了这种效果的第一个实验证据，并证明了极化激元自旋电流超过100 μ m的高品质的GaAs/AlGaAs量子微腔的传播。通过旋转激发光的偏振面，我们能够切换自旋流的方向。
The spin Hall effect consists of the generation of a spin current perpendicular to the charge current flow. Thirty-five years after its prediction by Dyakonov and Perel'(1), it is the focus of experimental and theoretical investigations and constitutes one of the most remarkable effects of spintronics. Owing to scattering and dephasing in electronic gases, it is difficult to observe and has only been demonstrated for the first time a few years ago(2-5). Recently, three of us have predicted the optical spin Hall effect(6), which consists of a separation in real space and momentum space of spin-polarized exciton-polaritons generated by a laser in a semiconductor microcavity(7). The separation takes place owing to a combination of elastic scattering of exciton-polaritons by structural disorder and an effective magnetic field coming from polarization splitting of the polariton states. The excitonic spin current is controlled by the linear polarization of the laser pump. Here, we report the first experimental evidence for this effect and demonstrate propagation of polariton spin currents over 100 mu m in a high-quality GaAs/AlGaAs quantum microcavity. By rotating the polarization plane of the exciting light, we were able to switch the directions of the spin currents.