Anisotropic Acoustic Plasmons in Black Phosphorus

In Ho Lee, Luis Martin-Moreno, Daniel A. Mohr, Kaveh Khaliji, Tony Low, Sang Hyun Oh

Research output: Contribution to journalArticle

12 Scopus citations


Acoustic plasmon modes tightly coupled between a two-dimensional material and another conducting layer can exhibit optical confinement not possible with conventional plasmons. Here, we investigate acoustic plasmons supported in a monolayer and multilayers of black phosphorus (BP) placed shortly above a conducting plate. In the presence of a conducting plate, the acoustic plasmon dispersion for the armchair direction is found to exhibit the characteristic linear scaling in the mid- and far-infrared regime while it largely deviates from that in the long-wavelength limit and near-infrared regime. For the zigzag direction, such scaling behavior is not evident due to relatively tighter plasmon confinement. Further, we demonstrate a novel design for an acoustic plasmon resonator that exhibits higher plasmon confinement and resonance efficiency than BP ribbon resonators in the mid-infrared and longer wavelength regime. The theoretical framework and new resonator designs studied here provide a practical route toward the experimental verification of acoustic plasmons in BP and open up the possibility to develop novel plasmonic and optoelectronic devices that can leverage its strong in-plane anisotropy and thickness-dependent band gap.

Original languageEnglish (US)
Pages (from-to)2208-2216
Number of pages9
JournalACS Photonics
Issue number6
StatePublished - Jun 2018


  • acoustic plasmon
  • anisotropy
  • black phosphorus
  • gap plasmon
  • surface plasmon polaritons
  • two-dimensional material

How much support was provided by MRSEC?

  • Primary

Reporting period for MRSEC

  • Period 4

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    MRSEC SEED Projects

    11/1/14 → …

    Project: Research project

    University of Minnesota MRSEC (DMR-1420013)

    Lodge, T. P.


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