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arXiv 1703.04239cond-mat.mes-hall
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外电场中石墨烯量子点的光学选择规则

The optical selection rules of a graphene quantum dot in external electric fields

Qing-Rui Dong, Chun-Xiang Liu

摘要:

理论研究了三种典型面内电场作用下的单电子三角形锯齿形石墨烯量子点。用紧束缚方法计算了量子点的远红外吸收谱,并与相应的能谱进行了对比,确定了量子点的光学选择规则。结果表明,由于量子点的C3对称性,存在显著的光学选择规则。当电场也具有C3对称性时,吸收光谱中只有两个吸收峰。随着电场对体系C3对称性的破坏,最强峰的强度和禁戒跃迁的数目都逐渐减小。此外,极化导致峰值强度降低,甚至产生新的禁戒跃迁。我们的研究结果可能有助于石墨烯量子点在电子和光电子器件中的应用。

英文摘要:

We study theoretically the single-electron triangular zigzag graphene quantum dot in three typical in-plane electric fields. The far-infrared absorption spectra of the dot are calculated by the tight-binding method and then the optical selection rules are identified by contrast with the corresponding energy spectra. Our result shows that there exist the remarkable optical selection rules due to the C3 symmetry of the dot. When the electric field possesses also the C3 symmetry, there are only two absorption peaks in the absorption spectra. As the C3 symmetry of the system is damaged by the electric fields, both the intensity of the strongest peak and the number of the forbidden transitions decrease gradually. Moreover, the polarization causes the decrease of the peak intensities and even new forbidden transitions. Our findings may be useful for the application of graphene quantum dots to electronic and optoelectronic devices.

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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