Atomic Engineering of Monolayer Graphene: Inducing Kekulé Bond Order by Adatom Deposition

ORAL

Abstract

The Kekulé distortion (KD) periodically modifies the carbon-carbon bonds in graphene, resulting in a √3×√3 R30° superstructure and symmetry breaking between three previously equivalent hexagonal plaquettes. Previous scanning tunnelling microscopy (STM) experiments have shown that such a distortion induced by vacancies in the graphene substrate can produce charge density modulations corresponding to the superstructure [1]. Here, we induce a KD phase in monolayer graphene by low-flux deposition of a small number of lithium adatoms. Using angle-resolved photoemission spectroscopy (ARPES), we observe backfolding of the Dirac cones to Γ, as well as a gap opening (2Δ = 0.22 ± 0.02 eV) at the Dirac point. Low-energy electron diffraction (LEED) measurements also show the appearance of peaks corresponding to the new periodicity. Finally, we discuss the real-space behaviour of the adatoms by comparing STM data with predictions by a Monte Carlo toy model.

References

[1] C. Gutiérrez, Nature Physics 12, 950–958 (2016).

*This research was undertaken thanks in part to funding from NSERC, CIFAR, CFREF, CFI, the BC Knowledge Development Fund, and the University of British Columbia.

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Presenters

  • Amy Qu

    • University of British Columbia

Authors

  • Amy Qu

    • University of British Columbia

  • Pascal Nigge

    • University of British Columbia

  • Christopher Gutierrez

    • University of British Columbia

  • Jisun Kim

    • Department of Physics & Astronomy, Louisiana State University
    • University of British Columbia
    • Stewart Blusson Quantum Matter Institute, University of British Columbia

  • Stefan Link

    • Max Planck Institute for Solid State Research

  • Giorgio Levy

    • University of British Columbia

  • Matteo Michiardi

    • University of British Columbia

  • Michael Schneider

    • University of British Columbia

  • Sergey Zhdanovich

    • University of British Columbia

  • Ulrich Starke

    • Max Planck Institute for Solid State Research

  • Douglas Andrew Bonn

    • University of British Columbia
    • Department of Physics & Astronomy, University of British Columbia
    • Stewart Blusson Quantum Matter Institute, University of British Columbia

  • Sarah A Burke

    • Stewart Blusson Quantum Matter Institute, University of British Columbia
    • University of British Columbia

  • Andrea Damascelli

    • University of British Columbia
    • Stewart Blusson Quantum Matter Institute, University of British Columbia