Graphene transistor based on tunable Dirac fermion optics

Ke Wang, Mirza M. Elahi, Lei Wang, K. M.Masum Habib, Takashi Taniguchi, Kenji Watanabe, James Hone, Avik W. Ghosh, Gil Ho Lee, Philip Kim

Research output: Contribution to journalArticlepeer-review

37 Scopus citations


We present a quantum switch based on analogous Dirac fermion optics (DFO), in which the angle dependence of Klein tunneling is explicitly utilized to build tunable collimators and reflectors for the quantum wave function of Dirac fermions. We employ a dual-source design with a single flat reflector, which minimizes diffusive edge scattering and suppresses the background incoherent transmission. Our gate-tunable collimator–reflector device design enables the quantitative measurement of the net DFO contribution in the switching device operation. We obtain a full set of transmission coefficients between multiple leads of the device, separating the classical contribution from the coherent transport contribution. The DFO behavior demonstrated in this work requires no explicit energy gap. We demonstrate its robustness against thermal fluctuations up to 230 K and large bias current density up to 10 2 A/m, over a wide range of carrier densities. The characterizable and tunable optical components (collimator–reflector) coupled with the conjugated source electrodes developed in this work provide essential building blocks toward more advanced DFO circuits such as quantum interferometers. The capability of building optical circuit analogies at a microscopic scale with highly tunable electron wavelength paves a path toward highly integrated and electrically tunable electron-optical components and circuits.

Original languageEnglish (US)
Pages (from-to)6575-6579
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number14
StatePublished - Apr 2 2019
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2019 National Academy of Sciences. All Rights Reserved.


  • Dirac fermion
  • Electron optics
  • Graphene
  • Quantum transport


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