Observation of flat bands in tunable semiconductor artificial graphene

ORAL

Abstract

Flat bands near M points in the Brillouin zone are key features of honeycomb symmetry in artificial graphene (AG) where electrons may condense into novel correlated phases. Here we report the realization of flat bands of AG in GaAs quantum well transistors where the electron density is tuned by applied back-gate voltages. Two new peaks in the low-temperature optical emission spectra are linked to the van-Hove singularity doublet of a pair of flat bands near M-points of AG. As the Fermi level is tuned to overlap the optical emission doublet, PL spectra display dramatic stability against changes in electron density that indicate interplays between key electron-electron interactions and the lattice with honeycomb symmetry [1].
[1] Physical Review Letters, submitted (2020)

*Supported by US NSF award DMR-1306976 and by US DOE grant DE-SC0010695. We are grateful to Shalom J. Wind and Vittorio Pellegrini for illuminating discussions.

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Presenters

  • Ziyu Liu

    • Columbia University

Authors

  • Ziyu Liu

    • Columbia University

  • Lingjie Du

    • Nanjing University & Columbia University
    • Nanjing University

  • Ken W. West

    • Princeton University
    • Princeton Institute for the Science and Technology of Materials (PRISM), Princeton University
    • Department of Electrical Engineering, Princeton University
    • Electrical Engineering, Princeton
    • Electrical Engineering, Princeton University
    • Princeton

  • Saeed Fallahi

    • Purdue University
    • Purdue Univ

  • Loren Pfeiffer

    • Princeton University
    • Princeton Institute for the Science and Technology of Materials (PRISM), Princeton University
    • Department of Electrical Engineering, Princeton University
    • Electrical Engineering, Princeton
    • Electrical Engineering, Princeton University
    • Princeton

  • Michael Manfra

    • Purdue University
    • Purdue Univ
    • Department of Physics and Astronomy and Microsoft Quantum Purdue, Purdue University, West Lafayette, Indiana 47907 USA
    • Department of Physics and Astronomy and Station Q Purdue, Purdue University
    • Niels Bohr Institute, Microsoft Station Q, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
    • Department of Physics and Astronomy, Purdue University
    • Birck Nanotechnology Center and Microsoft Quantum Purdue, Purdue University

  • Aron Pinczuk

    • Columbia University