Optical read-out of Coulomb staircases in a moiré superlattice via trapped interlayer trions

Hyeonjun Baek, Mauro Brotons-Gisbert, Aidan Campbell, Valerio Vitale, Johannes Lischner, Kenji Watanabe, Takashi Taniguchi, Brian D. Gerardot

Research output: Contribution to journalArticlepeer-review

23 Citations (Scopus)
29 Downloads (Pure)


Moiré patterns with a superlattice potential can be formed by vertically stacking two layered materials with a relative twist or lattice constant mismatch. In transition metal dichalcogenide-based systems, the moiré potential landscape can trap interlayer excitons (IXs) at specific atomic registries. Here, we report that spatially isolated trapped IXs in a molybdenum diselenide/tungsten diselenide heterobilayer device provide a sensitive optical probe of carrier filling in their immediate environment. By mapping the spatial positions of individual trapped IXs, we are able to spectrally track the emitters as the moiré lattice is filled with excess carriers. Upon initial doping of the heterobilayer, neutral trapped IXs form charged IXs (IX trions) uniformly with a binding energy of ~7 meV. Upon further doping, the empty superlattice sites sequentially fill, creating a Coulomb staircase: stepwise changes in the IX trion emission energy due to Coulomb interactions with carriers at nearest-neighbour moiré sites. This non-invasive, highly local technique can complement transport and non-local optical sensing techniques to characterize Coulomb interaction energies, visualize charge correlated states, or probe local disorder in a moiré superlattice.

Original languageEnglish
Pages (from-to)1237-1243
Number of pages7
JournalNature Nanotechnology
Issue number11
Early online date23 Sept 2021
Publication statusPublished - Nov 2021

ASJC Scopus subject areas

  • Bioengineering
  • Atomic and Molecular Physics, and Optics
  • Biomedical Engineering
  • General Materials Science
  • Condensed Matter Physics
  • Electrical and Electronic Engineering


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