Controlling quantum Hall edge state interaction in a graphene pn junction via device geometry modification

ORAL

Abstract

The electrostatic profile of a pn junction may determine the way quantized Landau level (LL) edge states interact with each other [1,2]. Edge states at an electrostatically smooth junction are spatially further apart than those at a relatively abrupt junction, which decreases the probability of edge states mixing. We present a way to control LL edge state interaction through device geometry modification. A pnJ device with an electrostatic junction profile comparable to the one presented in [2] was experimentally fabricated and measured; however, it has a new geometry that alters the LL edge state interaction. In this device, we observe the lowest and second lowest LL edge states mix with each other in the quantum Hall regime. This ability to tune LL mixing opens up a new degree of freedom to fine tune quantum Hall resistance values for scalable resistance standard application. [1] J. R. Williams, L. DiCarlo, and C. M. Marcus, Science 317, 638 (2007) [2] Nikolai N. Klimov, Son T. Le, et al., Phys. Rev. B: Rapid Comm. (2015)

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Authors

  • Son T. Le

    The National Institute Of Standards And Technology, The National Institute of Standards and Technology

  • Joseph Hagmann

    The National Institute Of Standards And Technology, The National Institute of Standards and Technology, NIST - Natl Inst of Stds & Tech

  • Guangjun Cheng

    The National Institute Of Standards And Technology, The National Institute of Standards and Technology

  • Angela R. Hight Walker

    The National Institute Of Standards And Technology, NIST - Natl Inst of Stds & Tech, National Institute of Standards and Technology, The National Institute of Standards and Technology, Engineering Physics Division, National Institute of Standards and Technology

  • Nikolai Klimov

    The National Institute Of Standards And Technology, The National Institute of Standards and Technology

  • David Newell

    The National Institute Of Standards And Technology, The National Institute of Standards and Technology

  • Curt Richter

    The National Institute Of Standards And Technology, The National Institute of Standards and Technology

  • Ji ung Lee

    Suny Polytechnic, State Univ of NY - Polytechnic Institute

  • Jun Yan

    University of Massachusetts at Amherst, Univ of Mass - Amherst, Department of Physics, UMass Amherst, Department of Physics