Research on the coherent control of electron spins in quantum dots

量子点电子自旋相干控制研究

• 批准号: 14350001
• 负责人: MUTO Shunichi
• 金额: $ 10.94万
• 依托单位: HOKKAIDO UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2002
• 资助国家: 日本
• 起止时间: 2002 至 2003
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-14350001/
• 关键词: coherent controle; electron spins; quantum dots; circular polarized light; relaxation time; exciton; lifetime; relaxation mechanism; 量子演算; 光スイッチ; 時間分解発光; スピン緩和

Self-assembled InAlAs/AlGaAs quantum dots are grown by the Stranski-Krastanow mode of Molecular Beam Epitaxy (MBE). We measured the spin relaxation time of the structure under the non-resonant optical excitation by using 80 fs pulses by the titanium sapphire laser at wavelength of 780 nm. We used the right circular polarized light for the excitation of carrires to obtain fixed electron spins. The luminescence from the quantum dots at 10 K was divided into the right circular and the left circular components and was temporary resolved by the streak-scope. While the lifetime of the exciton was about 1 18 ns, the spin relaxation time determined by the decay of the polarization of luminescence was 1.31 us, which is comparable to the lifetime. The result indicates that the major relaxation mechanisms in the quantum well are not effective in the quantum dots and that the quantum dot is a good material for the coherent control of electron spins.As the spin-electronisc material for the future generations, wide-gap semiconductors and a polymer was studied with emphasis on the magnetic or spintronic properties.

采用分子束外延(MBE)的STranski-Krastanow模式生长了InAlAs/AlGaAs自组装量子点。利用波长为780 nm的钛宝石激光，利用80ps脉冲测量了该结构在非共振光激励下的自旋弛豫时间。我们用右圆偏振光激发载流子获得了固定的电子自旋。在10K下，量子点的发光被分成右圆和左圆两个分量，并用扫描显微镜进行了暂时分辨。当激子寿命约为118 ns时，由发光极化衰减确定的自旋弛豫时间为1.31us，与寿命相当。结果表明，量子阱中的主要驰豫机制在量子点中是无效的，量子点是一种很好的相干控制电子自旋的材料。作为下一代的自旋电子化材料，宽禁带半导体和聚合物的研究重点是磁性或自旋电子学性质。

项目成果

S.Adachi, S.Muto, K.Hazu, T.Sota, K.Suzuki, et al.: "Exciton-exciton interaction and hetro-biexciton in GaN"Phys.Rev.B. 67. 205212/1-205212/5 (2003)

S.Adachi、S.Muto、K.Hazu、T.Sota、K.Suzuki 等人：“GaN 中的激子-激子相互作用和异质-双激子”Phys.Rev.B。

H.Sasakura, S.Adachi, S.Muto, et al.: "Spin Depolarization via Tunneling Effects in Asymmetric Double Quantum Dot Structure"Jpn.J.Appl.Phys.. 43, No.4B(in press). (2004)

H.Sasakura、S.Adachi、S.Muto 等人：“通过非对称双量子点结构中的隧道效应实现自旋去极化”Jpn.J.Appl.Phys.. 43，No.4B（印刷中）。

S.Adachi, K.Hazu, T.Sota, SF.Chichibu, (他4名): "Biexciton formation and exciton-exciton correlation effects in bulk ZnO"Semiconductor Science and Technology. 19. S276-S278 (2004)

S.Adachi、K.Hazu、T.Sota、SF.Chichibu，（其他 4 人）：“块状 ZnO 中的双激子形成和激子-激子相关效应”半导体科学与技术 19. S276-S278 (2004)。

S.Adachi, K.Hazu, T.Sota, SF.Chichibu, (他3名): "Scattering processes and dynamics of exciton-biexciton system in GaN"Proceedings of SPIE, Ultrafast Phenomena in Semiconductors VII. 4992. 188-201 (2003)

S.Adachi、K.Hazu、T.Sota、SF.Chichibu，（其他 3 人）：“GaN 中激子-双激子系统的散射过程和动力学”SPIE 论文集，半导体中的超快现象 VII 4992。188-201（ 2003）

K.Shiramine, T.Itoh, S.Muto, (他2名): "Adatom migration in Stranski-Krastanow growth of In As quantum dows"Journal of Crystal Growth. 242. 332-338 (2002)

K.Shiramine、T.Itoh、S.Muto，（另外 2 人）：“In As 量子道的 Stranski-Krastanow 生长中的原子迁移”《晶体生长杂志》242. 332-338 (2002)。