Hyperbolic Plasmon Polaritons in the Delafossite PdCoO2

ORAL

Abstract

Hyperbolic plasmon polaritons are uncommon light-matter modes in materials at the extreme of anisotropy - where metallic and dielectric characters coexist along different crystallographic directions. Using Kramers-Kronig analysis and finite-difference time-domain simulations, we have identified a new quasi-two-dimensional material, palladium cobaltate (PdCoO2), that is expected to support low-loss hyperbolic plasmon polaritons at infrared frequencies. Simulations are consistent with the polariton dispersion calculated from the complex reflection coefficient. The large optical anisotropy can be recognized by the order of magnitude difference between the in-plane and out-of-plane plasma frequencies. Scanning near-field optical microscopy can be used to study these light-matter modes. However, because hyperbolic polaritons travel inside the material and reflect off the surfaces, observing them requires a thin layer (50-150 nm) of PdCoO2 with smooth surfaces. This presents a challenge to an experimental demonstration of hyperbolic modes in PdCoO2 since the material does not exfoliate readily from flux-grown single crystals and forms twin domains in films grown by molecular beam epitaxy. Efforts to isolate flat, thin flakes of PdCoO2 for near-field measurements will be presented.

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Presenters

  • Francesco Ruta

    • Department of Physics, Columbia University

Authors

  • Francesco Ruta

    • Department of Physics, Columbia University

  • Seunghyun Khim

    • Max Planck Institute for Chemical Physics of Solids
    • Max Planck Institut for Chemical Physics of Solids
    • Max Planck Institute for Chemical Physics of Solids, Dresden, Germany

  • Gaurab Rimal

    • Rutgers University, New Brunswick
    • Physics, Rutgers University
    • Department of Physics and Astronomy, Rutgers University
    • University of Wyoming
    • Department of Physics and Astronomy, Rutgers, The State University of New Jersey

  • Brian S Y Kim

    • Columbia University, The Department of Mechanical Engineering
    • Mechanical Engineering, Columbia University
    • Department of Mechanical Engineering, Columbia University

  • Kevin Kam

    • Department of Electrical Engineering, Columbia University

  • Aaron Sternbach

    • Columbia Univ
    • Department of Physics, Columbia University
    • Physics, Columbia University

  • Yinming Shao

    • Physics, Columbia University
    • Department of Physics, Columbia University
    • Columbia University

  • Christopher Homes

    • Condensed Matter Physics and Materials Science Division, Brookhaven National Laboratory

  • Seongshik Oh

    • Physics, Rutgers University
    • Department of Physics and Astronomy, Rutgers University
    • Department of Physics and Astronomy, Rutgers, the state university of New Jersey
    • Department of Physics and Astronomy, Rutgers, The State University of New Jersey
    • Rutgers University, New Brunswick
    • Department of Physics & Astronomy, Rutgers, The State University of New Jersey

  • Andrew Mackenzie

    • Max Planck Institute for Chemical Physics of Solids
    • Max Planck Institut for Chemical Physics of Solids
    • Max Planck Institute for Chemical Physics of Solids, Dresden, Germany
    • MPI CPfS, Dresden, Germany

  • Dmitri Basov

    • Columbia University, The Department of Physics
    • Columbia University
    • Physics, Columbia University
    • Columbia Univ
    • Department of Physics, Columbia University