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arXiv · 1209.1689

Evidence for Superlattice Dirac Points and Space-dependent Fermi Velocity in Corrugated Graphene Monolayer

Hui Yan·Zhao-Dong Chu·Wei Yan·Mengxi Liu·Lan Meng·Mudan Yang·Yide Fan·Jiang Wang·Rui-Fen Dou·Yanfeng Zhang·Zhongfan Liu·Jia-Cai Nie·Lin He
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Abstract

Recent studies show that periodic potentials can generate superlattice Dirac points at energies in graphene (is the Fermi velocity of graphene and G is the reciprocal superlattice vector). Here, we perform scanning tunneling microscopy and spectroscopy studies of a corrugated graphene monolayer on Rh foil. We show that the quasi-periodic ripples of nanometer wavelength in the corrugated graphene give rise to weak one-dimensional (1D) electronic potentials and thereby lead to the emergence of the superlattice Dirac points. The position of the superlattice Dirac point is space-dependent and shows a wide distribution of values. We demonstrated that the space-dependent superlattice Dirac points is closely related to the space-dependent Fermi velocity, which may arise from the effect of the local strain and the strong electron-electron interaction in the corrugated graphene.

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Hui Yan, Zhao-Dong Chu, Wei Yan, Mengxi Liu, Lan Meng, Mudan Yang, Yide Fan, Jiang Wang, Rui-Fen Dou, Yanfeng Zhang, Zhongfan Liu, Jia-Cai Nie, Lin He. 2012-11-06. Evidence for Superlattice Dirac Points and Space-dependent Fermi Velocity in Corrugated Graphene Monolayer. https://doi.org/10.1103/physrevb.87.075405

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