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arXiv 0902.2130cond-mat.mes-hallcond-mat.str-el
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量子点中关联电子的分子态

A molecular state of correlated electrons in a quantum dot

Sokratis Kalliakos, Massimo Rontani, Vittorio Pellegrini, Cesar Pascual Garcia, Aron Pinczuk, Guido Goldoni, Elisa Molinari, Loren N. Pfeiffer, Ken W. West

摘要:

有限量子系统中粒子之间的关联导致了复杂的行为和新的物质状态。一个值得注意的例子被预测发生在半导体量子点(QD)中,在密度为零的情况下,电子之间的库仑相关性将它们的相对位置刚性地固定为分子中原子核的相对位置。在此极限下,中性少体激振是具有刚性转子或相对运动特性的转子振动。相反,在弱相关区域,科里奥利力混合了旋转和振动运动。在这里,我们报告的证据旋转振动模式的电子分子状态的密度,电子本地化尚未完全实现。我们探测这些集体模式的非弹性光散射量子点含有四个电子。与相对运动波函数(与传统分子的振动模式类似)的变化相关的低位激发谱不依赖于由总角动量表示的转动状态。通过构型相互作用(CI)方法的理论模拟与所观察到的旋转振动模式一致,并表明这种分子激发发展在发病的短程相关。

英文摘要:

Correlation among particles in finite quantum systems leads to complex behaviour and novel states of matter. One remarkable example is predicted to occur in a semiconductor quantum dot (QD) where at vanishing density the Coulomb correlation among electrons rigidly fixes their relative position as that of the nuclei in a molecule. In this limit, the neutral few-body excitations are roto-vibrations, which have either rigid-rotor or relative-motion character. In the weak-correlation regime, on the contrary, the Coriolis force mixes rotational and vibrational motions. Here we report evidence of roto-vibrational modes of an electron molecular state at densities for which electron localization is not yet fully achieved. We probe these collective modes by inelastic light scattering in QDs containing four electrons. Spectra of low-lying excitations associated to changes of the relative-motion wave function -the analogues of the vibration modes of a conventional molecule- do not depend on the rotational state represented by the total angular momentum. Theoretical simulations via the configuration-interaction (CI) method are in agreement with the observed roto-vibrational modes and indicate that such molecular excitations develop at the onset of short-range correlation.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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