Aberration-corrected STEM imaging of 2D materials: Artifacts and practical applications of threefold astigmatism

Sergei Lopatin, Areej Aljarb, Vladimir Roddatis, Tobias Meyer, Yi Wan, Jui-Han Fu, Mohamed N. Hedhili, Yimo Han, Lain-Jong Li, Vincent Tung

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

High-resolution scanning transmission electron microscopy (HR-STEM) with spherical aberration correction enables researchers to peer into two-dimensional (2D) materials and correlate the material properties with those of single atoms. The maximum intensity of corrected electron beam is confined in the area having sub-angstrom size. Meanwhile, the residual threefold astigmatism of the electron probe implies a triangular shape distribution of the intensity, whereas its tails overlap and thus interact with several atomic species simultaneously. The result is the resonant modulation of contrast that interferes the determination of phase transition of 2D materials. Here, we theoretically reveal and experimentally determine the origin of resonant modulation of contrast and its unintended impact on violating the power-law dependence of contrast on coordination modes between transition metal and chalcogenide atoms. The finding illuminates the correlation between atomic contrast, spatially inequivalent chalcogenide orientation, and residual threefold astigmatism on determining the atomic structure of emerging 2D materials.
Original languageEnglish (US)
Pages (from-to)eabb8431
JournalScience advances
Volume6
Issue number37
DOIs
StatePublished - Sep 9 2020

Bibliographical note

KAUST Repository Item: Exported on 2020-10-01
Acknowledged KAUST grant number(s): OSR-2018-CARF/CCF-3079
Acknowledgements: V.T., A.A., and J.-H.F. are indebted to the support from the King Abdullah University of Science and Technology (KAUST) Office of Sponsored Research (OSR) under award no. OSR-2018-CARF/CCF-3079. V.T. acknowledges the support from User Proposals (nos. 5067 and 5424) at the Molecular Foundry, Lawrence Berkeley National Laboratory, supported by the Office of Basic Energy Sciences, of the U.S. Department of Energy under contract no. DE-AC02-05CH11231. The financial support from the Deutsche Forschungsgemeinschaft (DFG) via the CRC 1073 project Z02 and B02 is acknowledged.

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