• 文献标题:   Symmetry breaking in molecular artificial graphene
  • 文献类型:   Article
  • 作  者:   YAN LH, HUA MQ, ZHANG QS, NGAI E, GUO ZS, WU C, WANG T, LIN N
  • 作者关键词:   artificial graphene, gap opening, scanning tunneling spectroscopy, molecular designer
  • 出版物名称:   NEW JOURNAL OF PHYSICS
  • ISSN:   1367-2630
  • 通讯作者地址:   Hong Kong Univ Sci Technol
  • 被引频次:   3
  • DOI:   10.1088/1367-2630/ab34a6
  • 出版年:   2019

▎ 摘  要

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.