Atom Identification in Bilayer Moiré Materials with Gomb-Net

Austin C. Houston, Sumner B. Harris, Hao Wang, Yu Chuan Lin, David Geohegan, Kai Xiao, Gerd Duscher

Research output: Contribution to journalArticlepeer-review

Abstract

Moiré patterns in van der Waals bilayer materials complicate the analysis of atomic-resolution images, hindering the atomic-scale insight typically attainable with scanning transmission electron microscopy. Here, we report a method to detect the positions and identities of atoms in each of the individual layers that compose twisted bilayer heterostructures. We developed a deep learning model, Gomb-Net, which identifies the coordinates and atomic species in each layer, deconvoluting the moiré pattern. This enables layer-specific mapping of atomic positions and dopant distributions, unlike other commonly used segmentation models which struggle with moiré-induced complexity. Using this approach, we explored the Se atom substitutional site distribution in a twisted fractional Janus WS2-WS2(1-x)Se2x heterostructure and found that layer-specific implantation sites are unaffected by the moiré pattern’s local energetic or electronic modulation. This advancement enables atom identification within material regimes where it was not possible before, opening new insights into previously inaccessible material physics.

Original languageEnglish
Pages (from-to)9277-9284
Number of pages8
JournalNano Letters
Volume25
Issue number23
DOIs
StatePublished - Jun 11 2025

Funding

This work was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division. Development of machine learning methods was supported by the Center for Nanophase Materials Sciences (CNMS), which is a U.S. Department of Energy, Office of Science User Facility at Oak Ridge National Laboratory. The microscopy and machine learning in this work was partially supported by the AI Tennessee Initiative and the Electron Microscopy Center at the University of Tennessee, Knoxville. For the MOCVD growth of 2D WS crystals Y.-C.L. acknowledges funding from NEWLIMITS, a center in nCORE as part of the Semiconductor Research Corporation (SRC) program sponsored by NIST through award number 70NANB17H041. 2

Keywords

  • machine learning
  • moiré materials
  • scanning transmission electron microscopy
  • twisted bilayers

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