Open AccessSymmetry breaking in molecular artificial graphene
Author(s) -
Linghao Yan,
Muqing Hua,
Qiushi Zhang,
Tsz Ue Ngai,
Zesheng Guo,
Tsz Chun Wu,
Tong Wang,
Nian Lin
Publication year - 2019
Publication title -
new journal of physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.584
H-Index - 190
ISSN - 1367-2630
DOI - 10.1088/1367-2630/ab34a6
Subject(s) - physics , point reflection , graphene , symmetry breaking , condensed matter physics , scattering , lattice (music) , coronene , scanning tunneling spectroscopy , local symmetry , reflection symmetry , molecule , quantum tunnelling , quantum mechanics , geometry , mathematics , acoustics
Symmetry breaking in graphene has profound impacts on its physical properties. Here we emulate symmetry breaking in artificial graphene systems by assembling coronene molecules on a Cu(111) surface. We apply two strategies: (1) differentiating the on-site energy of two sublattices of a honeycomb lattice and (2) uniaxially compressing a honeycomb lattice. The first one breaks the inversion symmetry while the second one merges the Dirac cones. The scanning tunneling spectroscopy shows that in both cases the local density of states undergo characteristic changes. Muffin-tin simulations reveal that the observed changes are associated with a band gap opened at the Dirac point. Furthermore, we propose that using larger molecules or molecules strongly scattering the surface state electrons can induce an indirect gap.