Superlattice Dirac points and space-dependent Fermi velocity in a corrugated graphene monolayer

作者：Yan, Hui; Chu, Zhao-Dong; Yan, Wei; Liu, Mengxi; Meng, Lan; Yang, Mudan; Fan, Yide; Wang, Jiang; Dou, Rui-Fen; Zhang, Yanfeng; Liu, Zhongfan; Nie, Jia-Cai; He, Lin^*

来源：Physical Review B, 2013, 87(7): 075405.

DOI：10.1103/PhysRevB.87.075405

• ELECTRONIC-PROPERTIES
• SCALE
• MOIRE
• FOILS

Recent studies show that periodic potentials can generate superlattice Dirac points at energies +/-(h) over bar nu(F)vertical bar G vertical bar/2 in graphene (where (h) over bar is the reduced Planck constant, nu(F) 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 quasiperiodic ripples of nanometer wavelength in the corrugated graphene give rise to weak one-dimensional 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 demonstrate that the space-dependent superlattice Dirac points are 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. DOI: 10.1103/PhysRevB.87.075405

• 出版日期2013-2-4
• 单位北京大学; 北京师范大学