Coherent transport and manipulation of spins in indirect-exciton nanostructures
Coherent transport and manipulation of spins in indirect-exciton nanostructures
复制标题
间接激子纳米结构中自旋的相干传输和操纵
DOI：
--
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
P. Santos
中科院分区：
文献类型：
--
作者：
A. Violante;R. Hey;P. Santos
本文报道了GaAs双量子阱（DQW）纳米结构中间接激子（IX）自旋的相干控制和输运。利用聚焦的圆偏振光斑产生自旋，利用空间分辨和偏振分辨光致发光光谱探测自旋的空间分布，研究了自旋动力学。光注入激子在距离激发点超过20 {mu}m的距离上进行自旋进动，其空间进动频率取决于自旋输运方向以及施加在DQW结构上的偏置。这种行为归因于自旋轨道相互作用引起的有效磁场中的自旋进动。根据自旋动力学对输运方向、偏置和外磁场的依赖关系，我们直接确定了结构的Dresselhaus和Rashba自旋分裂系数。旋进动力学基本上与IX密度无关，因此表明长自旋寿命与IX集体效应无关。后者以及空穴对自旋动力学的贡献可以忽略不计，更大程度上归因于电场使电子和空穴波函数在空间上分离，从而降低了电子-空穴交换相互作用。长输运距离上的相干自旋进动以及利用电场和磁场对自旋矢量的控制为IX自旋在量子信息处理中的应用开辟了道路。
We report on the coherent control and transport of indirect exciton (IX) spins in GaAs double quantum well (DQW) nanostructures. The spin dynamics was investigated by optically generating spins using a focused, circularly polarized light spot and by probing their spatial distribution using spatially and polarization resolved photoluminescence spectroscopy. Optically injected exciton spins precess while diffusing over distances exceeding 20 {mu}m from the excitation spot with a spatial precession frequency that depends on the spin transport direction as well as on the bias applied across the DQW structure. This behavior is attributed to the spin precession in the effective magnetic field induced by the spin-orbit interaction. From the dependence of the spin dynamics on the transport direction, bias and external magnetic fields we directly determined the Dresselhaus and Rashba spin splitting coefficients for the structure. The precession dynamics is essentially independent on the IX density, thus indicating that the long spin lifetimes are not associated with IX collective effects. The latter, together with the negligible contribution of holes to the spin dynamics, are rather attributed to spatial separation of the electron and hole wave functions by the electric field, which reduces the electron-hole exchange interaction. Coherent spin precession over long transport distances as well as the control of the spin vector using electric and magnetic fields open the way for the application of IX spins in the quantum information processing.
基于声学传输的远程间接激子系统的可扩展互连
影响因子：
3.7
作者：
S. Lazic;A. Violante;K. Cohen;R. Hey;R. Rapaport;P. V. Santos
通讯作者：
P. V. Santos