Dynamics of optically induced nuclear spin polarization in individual InPOGaxIn1-xP quantum dots
Dynamics of optically induced nuclear spin polarization in individual InPOGaxIn1-xP quantum dots
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DOI：
10.1103/physrevb.81.245308
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发表时间：
2010-06-09
影响因子：
3.7
通讯作者：
Tartakovskii, A. I.
中科院分区：
文献类型：
--
作者：
Chekhovich, E. A.;Makhonin, M. N.;Tartakovskii, A. I.
本文报道了在T= 4.2K时InP/GaInP量子点中光致核自旋极化的动力学。研究了在名义上未掺杂的样品中由残余掺杂引起的具有不同电荷状态的点。在同一个样本中，我们发现在黑暗中的核自旋衰变时间从类似于85到类似于6000 s的强烈点到点变化。测得的最长的衰减时间是可比的那些先前测量的散装InP和对应于几乎完全抑制核自旋扩散出的点。在带负电荷的点中，自旋衰减时间超过300 s（最慢的衰减类似于6000 s），比先前在门控结构中的电子带电点中报道的时间长约105倍。我们讨论了可能的机制负责抑制核自旋扩散，包括不均匀的四极位移和超精细相互作用与电子限制在点的稳定效果。
We report on dynamics of optically induced nuclear spin polarization in individual InP/GaInP quantum dots at T=4.2 K. Dots with different charge states arising from residual doping in a nominally undoped sample have been studied. In the same sample, we find strong dot-to-dot variation in the nuclear spin decay times in the dark from similar to 85 to similar to 6000 s. The longest decay times measured are comparable to those previously measured in bulk InP and correspond to almost complete suppression of nuclear spin diffusion out of the dot. In the negatively charged dots, the spin decay times exceed 300 s (with the slowest decay of similar to 6000 s), about 105 times longer than those reported previously in electron charged dots in gated structures. We discuss possible mechanisms responsible for suppression of nuclear spin diffusion, including inhomogeneous quadrupolar shifts and stabilizing effect of the hyperfine interaction with the electron confined in the dot.