Graphene on incommensurate substrates: trigonal warping and emerging Dirac cone replicas with halved group velocity
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TLDR
In this paper, it was shown that the small lattice incommensurability prevents the opening of this gap and rather leads to a renormalized Dirac dispersion with a trigonal warping, which breaks the effective time-reversal symmetry in a single valley.Abstract:
The adhesion of graphene on slightly lattice-mismatched surfaces, for instance, of hexagonal boron nitride (hBN) or Ir(111), gives rise to a complex landscape of sublattice symmetry-breaking potentials for the Dirac fermions. Whereas a gap at the Dirac point opens for perfectly lattice-matched graphene on hBN, we show that the small lattice incommensurability prevents the opening of this gap and rather leads to a renormalized Dirac dispersion with a trigonal warping. This warping breaks the effective time-reversal symmetry in a single valley. On top of this an additional set of massless Dirac fermions is generated, which is characterized by a group velocity that is about half the one of pristine graphene.read more
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Journal ArticleDOI
Cloning of Dirac fermions in graphene superlattices
Leonid Ponomarenko,Roman V. Gorbachev,Geliang Yu,D. C. Elias,Rashid Jalil,Aavishkar A. Patel,Artem Mishchenko,A. S. Mayorov,Colin R. Woods,John Wallbank,Marcin Mucha-Kruczynski,Benjamin A. Piot,Marek Potemski,Irina V. Grigorieva,K. S. Novoselov,Francisco Guinea,Vladimir I. Fal'ko,Andre K. Geim +17 more
TL;DR: Graphene superlattices such as this one provide a way of studying the rich physics expected in incommensurable quantum systems and illustrate the possibility of controllably modifying the electronic spectra of two-dimensional atomic crystals by varying their crystallographic alignment within van der Waals heterostuctures.
Journal ArticleDOI
Emergence of superlattice Dirac points in graphene on hexagonal boron nitride
Matthew Yankowitz,Jiamin Xue,Daniel Cormode,Javier Sanchez-Yamagishi,Kenji Watanabe,Takashi Taniguchi,Pablo Jarillo-Herrero,Philippe Jacquod,Philippe Jacquod,Brian J. LeRoy +9 more
TL;DR: In this article, it was shown that graphene deposited on hexagonal boron nitride produces moire patterns in scanning tunnelling microscopy images and that the interaction that produces this pattern also produces a commensurate periodic potential that generates a set of Dirac points that are different from those of the graphene lattice itself.
Emergence of Superlattice Dirac Points in Graphene on
Matthew Yankowitz,Jiamin Xue,Daniel Cormode,Kenji Watanabe,Takashi Taniguchi,Philippe Jacquod,Brian J. LeRoy +6 more
TL;DR: In this paper, it was shown experimentally and theoretically that the Moire pattern acts as a weak periodic potential and thereby leads to the emergence of a new set of Dirac points at an energy determined by its wavelength.
Journal ArticleDOI
Dirac materials
TL;DR: A wide range of materials, such as d-wave superconductors, graphene, and topological insulators, share a fundamental similarity: their low-energy fermionic excitations behave as massless Dirac particles rather than fermions obeying the usual Schrodinger Hamiltonian as mentioned in this paper.
Journal ArticleDOI
Twist-controlled resonant tunnelling in graphene/boron nitride/graphene heterostructures
Artem Mishchenko,J. S. Tu,Y. Cao,Roman V. Gorbachev,John Wallbank,Mark Greenaway,V. E. Morozov,Sergey V. Morozov,Mengjian Zhu,Swee Liang Wong,Freddie Withers,Colin R. Woods,Y-J Kim,Kenji Watanabe,T. Taniguchi,E. E. Vdovin,Oleg Makarovsky,T. M. Fromhold,Vladimir I. Fal'ko,Andre K. Geim,Laurence Eaves,Konstantin S. Novoselov +21 more
TL;DR: It is demonstrated how careful alignment of the crystallographic orientation of two graphene electrodes separated by a layer of hexagonal boron nitride in a transistor device can achieve resonant tunnelling with conservation of electron energy, momentum and, potentially, chirality.
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Related Papers (5)
Cloning of Dirac fermions in graphene superlattices
Leonid Ponomarenko,Roman V. Gorbachev,Geliang Yu,D. C. Elias,Rashid Jalil,Aavishkar A. Patel,Artem Mishchenko,A. S. Mayorov,Colin R. Woods,John Wallbank,Marcin Mucha-Kruczynski,Benjamin A. Piot,Marek Potemski,Irina V. Grigorieva,K. S. Novoselov,Francisco Guinea,Vladimir I. Fal'ko,Andre K. Geim +17 more