Voltage control of the spin dynamics of an exciton in a semiconductor quantum dot.
Voltage control of the spin dynamics of an exciton in a semiconductor quantum dot.
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DOI：
10.1103/physrevlett.94.197402
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发表时间：
2005-05
影响因子：
8.6
通讯作者：
Jason M. Smith;P. Dalgarno;R. Warburton;A. Govorov;K. Karrai;B. Gerardot;B. Gerardot;P. Petroff
中科院分区：
文献类型：
--
作者：
Jason M. Smith;P. Dalgarno;R. Warburton;A. Govorov;K. Karrai;B. Gerardot;B. Gerardot;P. Petroff
本文报道了在量子点中观察到的自旋-翻转过程，其中一个总角动量为L=2的暗激子变成了一个总角动量为1的亮激子。自旋-翻转过程被揭示在非对称激发后的衰变动力学中。我们能够简单地通过直流电压控制自旋翻转速率超过一个数量级。自旋翻转机制包括在我们的装置的背面接触中与费米海的自旋交换，并对应于高温近藤区域。我们用Anderson哈密顿量计算了自旋翻转速率，发现与实验结果符合得很好。
We report the observation of a spin-flip process in a quantum dot whereby a dark exciton with total angular momentum L = 2 becomes a bright exciton with L = 1. The spin-flip process is revealed in the decay dynamics following nongeminate excitation. We are able to control the spin-flip rate by more than an order of magnitude simply with a dc voltage. The spin-flip mechanism involves a spin exchange with the Fermi sea in the back contact of our device and corresponds to the high temperature Kondo regime. We use the Anderson Hamiltonian to calculate a spin-flip rate, and we find excellent agreement with the experimental results.