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Quantum confinement in graphene quantum dots
Author(s) -
Huang Zhongkai,
Qu Jinfeng,
Peng Xiangyang,
Liu Wenliang,
Zhang Kaiwang,
Wei Xiaolin,
Zhong Jianxin
Publication year - 2014
Publication title -
physica status solidi (rrl) – rapid research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.786
H-Index - 68
eISSN - 1862-6270
pISSN - 1862-6254
DOI - 10.1002/pssr.201409064
Subject(s) - quantum dot , coulomb blockade , physics , coulomb , condensed matter physics , graphene quantum dot , graphene , oscillation (cell signaling) , phase diagram , quantum mechanics , charge (physics) , charge density , gaussian , chemistry , phase (matter) , electron , biochemistry , transistor , voltage
By performing density functional theory calculations, we studied the quantum confinement in charged graphene quantum dots (GQDs), which is found to be clearly edge and shape dependent. It is found that the excess charges have a large distribution at the edges of the GQD. The resulting energy spectrum shift is very nonuniform and hence the Coulomb diamonds in the charge stability diagram vary irregularly, in good agreement with the observed nonperiodic Coulomb blockade oscillation. We also illustrate that the level statistics of the GQDs can be described by a Gaussian distribution, as predicted for chaotic Dirac billiards.The charge stability diagram (left) and the Gaussian distribution of the width of the Coulomb diamonds (right), indicating the nonperiodic Coulomb blockade oscillation in GQD due to quantum confinement. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)