• 文献标题:   Valley-momentum locking in a graphene superlattice with Y-shaped Kekule bond texture
  • 文献类型:   Article
  • 作  者:   GAMAYUN OV, OSTROUKH VP, GNEZDILOV NV, ADAGIDELI I, BEENAKKER CWJ
  • 作者关键词:   graphene, kekule distortion, valleymomentum locking, massless dirac fermion
  • 出版物名称:   NEW JOURNAL OF PHYSICS
  • ISSN:   1367-2630
  • 通讯作者地址:   Leiden Univ
  • 被引频次:   8
  • DOI:   10.1088/1367-2630/aaa7e5
  • 出版年:   2018

▎ 摘  要

Recent experiments by Gutierrez et al (2016 Nat. Phys. 12 950) on a graphene-copper superlattice have revealed an unusual Kekule bond texture in the honeycomb lattice-a Y-shaped modulation of weak and strong bonds with a wave vector connecting two Dirac points. We show that this so-called 'Kek-Y' texture produces two species of massless Dirac fermions, with valley isospin locked parallel or antiparallel to the direction of motion. In a magnetic field B, the valley degeneracy of the B-dependent Landau levels is removed by the valley-momentum locking but a B-independent and valley-degenerate zero-mode remains.