Valley-selective Channels in Strained Graphene Wrinkles

ORAL

Abstract

Pristine graphene has two degenerate valleys with linear dispersion. Under the influence of strain, the shift of the carbon atoms generates a vector potential which can give rise to a so-called pseudo-magnetic (PM) field. Unlike a real magnetic field, the PM field has opposite signs in the two valleys and provides a handle to control the valley degree of freedom. Theory has shown that in a strained wrinkle with Gaussian shape, the propagation of carriers along the wrinkle is valley-selective [1]. The carriers from one valley can only move in one direction while the ones from the other valley move in the opposite direction. By transferring single-layer graphene on top of an array of pillars fabricated on the surface of hBN, we generate strained wrinkles in a controllable way [2]. Measuring the magneto and Hall resistance as a function of field and carrier density at low temperatures, we observe a series of quantum conductance plateaus. Surprisingly, we find that all the plateaus are shifted by two units of quantum conductance. Using the Landauer-Buttiker formalism we show that this shift is a direct consequence of a valley selective channel along the wrinkle.
[1] Phys. Rev. B 94, 125422 (2016)
[2] Nano Lett. 17, 2839 (2017)

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Presenters

  • Junxi Duan

    Physics and Astronomy, Rutgers University, Department of Physics and Astronomy, Rutgers University

Authors

  • Junxi Duan

    Physics and Astronomy, Rutgers University, Department of Physics and Astronomy, Rutgers University

  • Xinyuan Lai

    Physics and Astronomy, Rutgers University, Department of Physics and Astronomy, Rutgers University

  • Jinhai Mao

    Department of Physics and Astronomy, Rutgers University, Physics, Rutgers, Physics and Astronomy, Rutgers University

  • Zhenyuan Zhang

    Physics and Astronomy, Rutgers University, Department of Physics and Astronomy, Rutgers University

  • Daiara Faria

    Instituto Politecnico, Universidade do Estado de Rio de Janeiro, Instituto Politecnico, Universidade do Estado do Rio de Janeiro, Physics, Instituto Politecnico do Rio de Janeiro, UERJ

  • Nancy Sandler

    Department of Physics and Astronomy, Ohio University, Ohio Univ, Physics and Astronomy, Ohio University

  • Eva Andrei

    Department of Physics and Astronomy, Rutgers University, Physics and Astronomy, Rutgers Univ, Physics and Astronomy, Rutgers University, Department of Physics and Astronomy, Rutgers the State Univ of NJ New Brunswick