Hybridization of electronic states in quantum dots through photon emission
Hybridization of electronic states in quantum dots through photon emission
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DOI：
10.1038/nature02109
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发表时间：
2004-01-08
期刊：
影响因子：
64.8
通讯作者：
Petroff, PM
中科院分区：
文献类型：
--
作者：
Karrai, K;Warburton, RJ;Petroff, PM
半导体量子点的自组装为光子学开辟了新的机会。量子点通常被描述为“人造原子”，因为电子和空穴限制会产生离散的能级。这幅图可以从观察到的壳结构中得到证明，因为量子点充满激子（1）（束缚电子-空穴对）或电子（2）。离散能级已经在使用单个量子点作为发射器的单光子源中被最典型地利用（3-6）。在低温下，量子点（7-9）中激子的长相干时间增强了人造原子图像，激发了量子点在量子光学和量子信息处理中的应用。在这种情况下，量子点中的激子已经被相干地操纵（10-12）。我们在这里表明，量子点也可以拥有远远超出人工原子模型的电子态。这些态是局域量子点态和扩展连续态的相干杂交：它们在原子物理学中没有类似物。这些状态是由量子点发射光子产生的。我们展示了描述局域态和扩展态之间相互作用的新版本的安德森模型如何解释观察到的杂交。
The self-assembly of semiconductor quantum dots has opened up new opportunities in photonics. Quantum dots are usually described as 'artificial atoms', because electron and hole confinement gives rise to discrete energy levels. This picture can be justified from the shell structure observed as a quantum dot is filled either with excitons(1) (bound electron - hole pairs) or with electrons(2). The discrete energy levels have been most spectacularly exploited in single photon sources that use a single quantum dot as emitter(3-6). At low temperatures, the artificial atom picture is strengthened by the long coherence times of excitons in quantum dots(7-9), motivating the application of quantum dots in quantum optics and quantum information processing. In this context, excitons in quantum dots have already been manipulated coherently(10-12). We show here that quantum dots can also possess electronic states that go far beyond the artificial atom model. These states are a coherent hybridization of localized quantum dot states and extended continuum states: they have no analogue in atomic physics. The states are generated by the emission of a photon from a quantum dot. We show how a new version of the Anderson model that describes interactions between localized and extended states can account for the observed hybridization.