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arXiv 2003.02980cond-mat.mes-hall
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InAs/GaAs耦合量子点对隧穿共振光跃迁的光谱展宽

Spectral broadening of optical transitions at tunneling resonances in InAs/GaAs coupled quantum dot pairs

P. Kumar, C. Jennings, M. Scheibner, A. S. Bracker, S. G. Carter, D. Gammon

摘要:

我们报道了InAs/GaAs耦合量子点的光跃迁的线宽分析,作为偏置电压,温度和隧道耦合强度的函数。在空穴隧穿共振处观察到高达100 $μ$ eV的显著谱线展宽,其中空间直接激子态和间接激子态之间的相干隧道耦合最大化,对应于20 K下150 ns ${}^{-1}$的声子辅助跃迁速率。随着温度的升高,谱线宽度呈现出单声子跃迁的展宽特征。作为隧道耦合强度的函数的线宽跟踪由于声子辅助跃迁的线宽加宽的理论预测,并最大化与0.8 $-$ 0.9毫电子伏的两个激子分支之间的能量分裂。这份报告强调了这些系统和当地环境之间的相互作用的线宽展宽机制和基本方面。

英文摘要:

We report on linewidth analysis of optical transitions in InAs/GaAs coupled quantum dots as a function of bias voltage, temperature, and tunnel coupling strength. A significant line broadening up to 100 $μ$eV is observed at hole tunneling resonances where the coherent tunnel coupling between spatially direct and indirect exciton states is maximized, corresponding to a phonon-assisted transition rate of 150 ns${}^{-1}$ at 20 K. With increasing temperature, the linewidth shows broadening characteristic of single-phonon transitions. The linewidth as a function of tunnel coupling strength tracks the theoretical prediction of linewidth broadening due to phonon-assisted transitions, and is maximized with an energy splitting between the two exciton branches of 0.8$-$0.9 meV. This report highlights the linewidth broadening mechanisms and fundamental aspects of the interaction between these systems and the local environment.

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