Research

Quantum and 2D materials in nanogaps

Can a nanogap drive a material into states it cannot reach on its own?

Materials are usually chosen for their intrinsic properties. We explore the reverse: an environment that activates behavior the material cannot show on its own. Nanogap cavities have already turned slow materials into ultrafast photodetectors and produced nonlinear responses absent from the bulk.

The direction we are opening is driven quantum matter at the nanoscale. Floquet engineering — reshaping a material’s energy levels with a strong light field — normally needs fields that heat and damage a sample. A nanogap reaches the same fields at ten-thousandth of the pulse energy, in a single 50 nm patch, without the heating that limits conventional Floquet experiments. We combine this with the other things a nanogap uniquely provides: vertical fields that reach dark and interlayer excitons, field gradients, local gating through the gap, and registered arrays that read magnetic and correlated order one cavity at a time.

Key papers

• Tailored emission spectrum of 2D semiconductors using plasmonic nanocavities
  J. Huang, G. M. Akselrod, T. Ming, J. Kong, M. H. Mikkelsen, ACS Photonics 5, 552⁠–⁠558 (2018) · DOI — ACS Editors' Choice
• Leveraging nanocavity harmonics for control of optical processes in 2D semiconductors
  G. M. Akselrod, T. Ming, C. Argyropoulos, T. B. Hoang, Y. Lin, X. Ling, D. R. Smith, J. Kong, M. H. Mikkelsen, Nano Letters 15, 3578⁠–⁠3584 (2015) · DOI
• Ultrafast pyroelectric photodetection with on-chip spectral filters
  J. W. Stewart, J. H. Vella, W. Li, S. Fan, M. H. Mikkelsen, Nature Materials 19, 158⁠–⁠162 (2020) · DOI
• Uncovering the mechanisms of triplet-triplet annihilation upconversion enhancement via plasmonic nanocavity tuning
  R. E. Bangle, H. Li, M. H. Mikkelsen, ACS Nano 17, 24022⁠–⁠24032 (2023) · DOI