Optical read-out of Coulomb staircases in a moiré superlattice via trapped interlayer trions
File(s)
Published version
Author(s)
Type
Journal Article
Abstract
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.
Date Issued
2021-09-23
Date Acceptance
2021-07-26
Citation
Nature Nanotechnology, 2021, 16, pp.1237-1243
ISSN
1748-3387
Publisher
Springer Science and Business Media LLC
Start Page
1237
End Page
1243
Journal / Book Title
Nature Nanotechnology
Volume
16
Copyright Statement
© The Author(s) 2021. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.
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Sponsor
Engineering & Physical Science Research Council (EPSRC)
Identifier
https://www.nature.com/articles/s41565-021-00970-9
Grant Number
EP/S025324/1
Subjects
Nanoscience & Nanotechnology
Publication Status
Published
Date Publish Online
2021-09-23