Band engineering of semiconductor artificial graphene and exploration of flat band physics(*)

ORAL

Abstract

Semiconductor artificial graphene (AG) has been realized on 2D electron systems in GaAs quantum wells subjected to a lateral potential modulation with honeycomb symmetry [1, 2]. Tunability of the AG band structure is a key property of the artificial systems. Here, we present effective band engineering of semiconductor AG with multiple control knobs that offer flexible and effective exclusive tunability of electron properties. Using the cutting-edge fabrication technology, we fabricated small-period triangular antidot lattices with different honeycomb lattice periods (35 nm to 45 nm) and various AG potentials. The M-point gap, which reveals key characteristics of the AG band structure, was measured by intersubband excitations using resonant inelastic light scattering (RILS) at low temperature. We found that the M-point gap could be tuned from 0.5 meV to 1.2 meV, with the band dispersion near the M point evolving from the Dirac-like case to flat band. Emerging flat-band physics in such tunable system will be discussed. [1] S. Wang, et al. Nature Nanotech. 13, 29 (2018). [2] L. Du, et al., Nature Commun. 9, 3299 (2018).

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Presenters

  • Lingjie Du

    Department of Applied Physics and Applied Mathematics, Columbia University

Authors

  • Lingjie Du

    Department of Applied Physics and Applied Mathematics, Columbia University

  • Loren Pfeiffer

    Electrical Engineering, Princeton University, Princeton University, Princeton Univ, Department of Electrical Engineering, Princeton University, PRISM, Princeton University, Physics, Princeton University, Electrical Engineering, Princeton

  • Kenneth West

    Electrical Engineering, Princeton University, Princeton University, Princeton Univ, Department of Electrical Engineering, Princeton University, PRISM, Princeton University, Physics, University of Pittsburgh, Electrical Engineering, Princeton

  • Saeed Fallahi

    Department of Physics and Astronomy, Purdue University, West Lafayette, Indiana 47907 USA, Purdue University, Department of Physics and Astronomy, Purdue University, Dept. of Physics, Purdue University, Dept. of Physics and Astronomy, Purdue

  • Geoffrey Gardner

    Department of Physics and Astronomy, Purdue University, Purdue University, Birck Nano Technology Center, Purdue University, Dept. of Physics, Purdue University, Department of Physics and Astronomy and Station Q Purdue, Purdue University, Department of Physics and Astronomy, Station Q Purdue, and Birck Nanotechnology Center, Purdue University

  • Michael Manfra

    Purdue University, Microsoft, Department of Physics and Astronomy and Station Q Purdue, Purdue University, Department of Physics and Astronomy, Purdue University, Department of Physics and Astronomy, Purdue University, West Lafayette, Indiana 47907 USA, Microsoft Station Q Purdue, Physics and Astronomy, Purdue University, Department of Physics and Astronomy, School of Materials Engineering and School of Electrical and Computer Engineering, Purdue University, Station Q Purdue and Department of Physics and Astronomy, Purdue University, Dept. of Physics, Purdue University, Department of Physics and Astronomy and Station Q Purdue, Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, USA, Dept. of Physics and Astronomy, Purdue, Purdue University, Station Q Purdue, Department of Physics and Astronomy, Station Q Purdue, and Birck Nanotechnology Center, Purdue University

  • Vittorio Pellegrini

    Istituto Italiano di Tecnologia

  • Shalom Wind

    Department of Applied Physics and Applied Mathematics, Columbia University

  • Aron Pinczuk

    Department of Applied Physics and Applied Mathematics and Department of Physics, Columbia University