Spin Relaxation and Its Control of Change Tunable Quantum Dots

自旋弛豫及其对可调谐量子点变化的控制

基本信息

批准号：
18204028
负责人：
MASUMOTO Yasuaki
金额：
$ 31.78万
依托单位：
University of Tsukuba
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
2006
资助国家：
日本
起止时间：
2006 至 2007
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-18204028/
关键词：
InP Quantum dot Electron Spin Nuclear Spin Exciton Spin Relaxation Time Spin Polarization Change Tunable 荷電励起子円偏光度励起子微細構造ハンレ効果超微細構造相互作用

项目摘要

Spin dephasing relaxation and nuclear spin effects on the electron spin polarization in single electron doped InP quantum dots (QDs) were studied. When an InP QD is doped with one electron on average, a narrow Lorentzian dip with half-width of 4.6 mT appeared in the Hanle curve. The half-width 4.6 mT was ascribed to spin-dephasing relaxation of doped electrons constituting negative trions. The corresponding spin coherence time at 5 K is 1.7 ns, which is determined by the frozen fluctuation of nuclear spins in the QDs. With increase of temperature, the spin-dephasing rate of the doped electrons increases. Pump probe photoluminescence measurements of electron spin relaxation were used to estimate the time period TN of the Larmor precession of nuclear spins in the hyperfine field of electrons. We found TN to be s$ at 5 K, under the vanishing external magnetic field Measurements of electron spin polarization in the longitudinal magnetic field at 5 K indicated that the Overhauser field induced by the dynamic nuclear polarization increases linearly with the excitation power. The effective magnetic field of the frozen fluctuations of nuclear spins was found to be 15 mT.Resonant spin orientation of excitons was observed under linearly polarized quasiresonant excitation in neutral InP QDs. Under the longitudinal and tilted magnetic fields of 1.5 and 2.5 T, two anticrossings of bright and dark excitons take place. At the anticrossing points, bright and dark excitons mix with each other and the wave function mixing induces the resonant spin orientation. Time-resolved circular polarization clearly showed the resonant spin orientation due to mixing of bright and dark excitons at the anticrossing points. Dark excitons can work as the carrier and spin reservoir because of their long lifetime. We demonstrated that magnetic field can control the spin entanglement and the resonant spin orientation of QDs.

研究了对单电子掺杂INP量子点（QD）中电子自旋极化（QD）中电子自旋极化的自旋倾向和核自旋影响。当INP QD平均用一个电子掺杂时，Hanle曲线中出现了狭窄的Lorentzian DIP，半宽为4.6 MT。一半宽4.6吨归因于构成负trions的掺杂电子的自旋脱骨松弛。在5 K处的相应自旋相干时间为1.7 ns，这取决于QD中核自旋的冷冻波动确定。随着温度的升高，掺杂电子的自旋dephasing速率增加。使用电子自旋松弛的泵探针光致发光测量来估计电子超细磁场中核自旋的Larmor进动的时间周期。我们发现，在5 K中电子自旋极化的消失的外部磁场测量值下，在5 K处的TN为S $，在5 K处的电子自旋极化表明，动态核极化引起的过度大速度场随激发能力的线性增加。发现核自旋冷冻波动的有效磁场为15吨。在中性INP QD中线性极化的Quasiresonant激发下观察到激子的共振旋转方向。在1.5和2.5 t的纵向和倾斜的磁场下，发生了两个明亮和深色激子的抗骨骼。在抗骨骼点，明亮和深色激子相互混合，波函数混合会引起共振旋转方向。时间分辨的圆极化清楚地表明，由于在抗骨折点上将明亮和深色激子混合在一起而引起的共振旋转方向。黑暗的激子可以作为携带者和旋转储层工作，因为它们的寿命很长。我们证明磁场可以控制QD的自旋纠缠和共振旋转方向。

项目成果

期刊论文数量（102）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Resonant spin orientation at the exciton level anticrossing in InP quantum dots

DOI：
10.1103/physrevb.77.115331
发表时间：
2008-03
期刊：
Physical Review B
影响因子：
3.7
作者：
Y. Masumoto;Kenta Toshiyuki;Tsukasa Suzuki;M. Ikezawa
通讯作者：
Y. Masumoto;Kenta Toshiyuki;Tsukasa Suzuki;M. Ikezawa

Auto correlation measurements of photoluminescence from InP quantum dots

InP 量子点光致发光的自相关测量

DOI：
发表时间：
2007
期刊：
影响因子：
0
作者：
Akira Endo;and Yasuhiro Iye;K. Bando and Masumoto
通讯作者：
K. Bando and Masumoto

Microdisk and microringLasers of thiophene-phenylene co-oligomers embedded in Si/Si02 substrates

嵌入 Si/SiO2 基底中的噻吩-亚苯基共聚低聚物的微盘和微环激光器

DOI：
发表时间：
2007
期刊：
Adv. Mater. 19
影响因子：
0
作者：
F. Sasaki;S. Kobayashi;S. Haraichi;S. Fujiwara;K. Bando;Y. Masumoto and S. Hotta
通讯作者：
Y. Masumoto and S. Hotta

Optical anisotropy of excitons and biexcitons in InP quantum dots

InP量子点中激子和双激子的光学各向异性