title: Valley Filtering and Electronic Optics Using Polycrystalline Graphene.
abstract: In this Letter, both the manipulation of valley-polarized currents and the optical-like behaviors of Dirac fermions are theoretically explored in polycrystalline graphene. When strain is applied, the misorientation between two graphene domains separated by a grain boundary can result in a mismatch of their electronic structures. Such a discrepancy manifests itself in a strong breaking of the inversion symmetry, leading to perfect valley polarization in a wide range of transmission directions. In addition, these graphene domains act as different media for electron waves, offering the possibility to modulate and obtain negative refraction indexes.
authors.affiliation: Institute of Condensed Matter and Nanosciences, Université catholique de Louvain, Chemin des étoiles 8, B-1348 Louvain-la-Neuve, Belgium.
authors.forename: V Hung
authors.initials: VH
authors.lastname: Nguyen
authors.affiliation: Institute of Condensed Matter and Nanosciences, Université catholique de Louvain, Chemin des étoiles 8, B-1348 Louvain-la-Neuve, Belgium.
authors.forename: S
authors.initials: S
authors.lastname: Dechamps
authors.affiliation: Centre for Nanoscience and Nanotechnology, CNRS, Université Paris Sud, Université Paris-Saclay, 91405 Orsay, France.
authors.forename: P
authors.initials: P
authors.lastname: Dollfus
authors.affiliation: Institute of Condensed Matter and Nanosciences, Université catholique de Louvain, Chemin des étoiles 8, B-1348 Louvain-la-Neuve, Belgium.
authors.forename: J-C
authors.initials: JC
authors.lastname: Charlier