Coulomb interaction in quasibound states of graphene quantum dots

被引:25
作者
Fu, Zhong-Qiu [1 ]
Bai, Ke-Ke [1 ,2 ]
Ren, Ya-Ning [1 ]
Zhou, Jiao-Jiao [3 ]
He, Lin [1 ]
机构
[1] Beijing Normal Univ, Ctr Adv Quantum Studies, Dept Phys, Beijing 100875, Peoples R China
[2] Hebei Normal Univ, Inst Phys, Shijiazhuang 050024, Hebei, Peoples R China
[3] Anhui Jianzhu Univ, Dept Math & Phys, Hefei 230601, Peoples R China
基金
中国国家自然科学基金;
关键词
INSULATOR; CONSTANT;
D O I
10.1103/PhysRevB.101.235310
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
Coulomb interaction is of central importance in localized energy levels (bound states) or electronic flat bands and can result in many exotic quantum phases. In a graphene monolayer, the relativistic massless Dirac fermion nature of the charge carriers enables us to realize unprecedented quasibound states, which are trapped temporarily via whispering-gallery modes (WGMs), in circular graphene quantum dots (GQDs). Here we show that Coulomb interaction still plays a dominating role in determining the electronic properties of the temporarily confined quasibound states with the lifetime (trapping time) of similar to 10 fs. Our scanning tunneling microscopy and spectroscopy measurements demonstrate that the discrete quasibound state in a GQD will split into two peaks when it is partially filled. The energy separation of the two split peaks increases linearly with inverse effective radius of the GQDs, indicating that the splitting arises from the Coulomb interaction. Moreover, we show that the real-space distribution of the two split states separates in different regions of the GQD to reduce the Coulomb interaction, leading to the breaking of the WGM of the quasibound states.
引用
收藏
页数:6
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