• 文献标题:   Field-induced insulating states in a graphene superlattice
  • 文献类型:   Article
  • 作  者:   PEZZINI S, WIEDMANN S, MISHCHENKO A, HOLWILL M, GORBACHEV R, GHAZARYAN D, NOVOSELOV KS, ZEITLER U
  • 作者关键词:  
  • 出版物名称:   PHYSICAL REVIEW B
  • ISSN:   2469-9950 EI 2469-9969
  • 通讯作者地址:   Radboud Univ Nijmegen
  • 被引频次:   0
  • DOI:   10.1103/PhysRevB.99.045440
  • 出版年:   2019

▎ 摘  要

We report on high-field magnetotransport (B up to 35 T) on a gated superlattice based on single-layer graphene aligned on top of hexagonal boron nitride. The large-period moire modulation (approximate to 15 nm) enables us to access the Hofstadter spectrum in the vicinity of and above one flux quantum per superlattice unit cell (Phi/Phi(0) = 1 at B = 22 T). We thereby reveal, in addition to the spin-valley antiferromagnet at nu = 0, two insulating states developing in positive and negative effective magnetic fields from the main nu = 1 and nu = -2 quantum Hall states, respectively. We investigate the field dependence of the energy gaps associated with these insulating states, which we quantify from the temperature-activated peak resistance. Referring to a simple model of local Landau quantization of third-generation Dirac fermions arising at Phi/Phi(0) = 1, we describe the different microscopic origins of the insulating states and experimentally determine the energy-momentum dispersion of the emergent gapped Dirac quasiparticles.