University of Oulu

ACS Nano 2022, 16, 12, 21199–21207

Stacking fault induced symmetry breaking in van der Waals nanowires

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Author: Sutter, Eli1,2; Komsa, Hannu-Pekka3; Puretzky, Alexander A.4;
Organizations: 1Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska68588, United States
2Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln, Lincoln, Nebraska68588, United States
3Faculty of Information Technology and Electrical Engineering, University of Oulu, FI-90014, Oulu, Finland
4Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee37830, United States
5Department of Electrical and Computer Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska68588, United States
Format: article
Version: accepted version
Access: embargoed
Persistent link:
Language: English
Published: American Chemical Society, 2022
Publish Date: 2023-11-22


While traditional ferroelectrics are based on polar crystals in bulk or thin film form, two-dimensional and layered materials can support mechanisms for symmetry breaking between centrosymmetric building blocks, e.g., by creating low-symmetry interfaces in van der Waals stacks. Here, we introduce an approach toward symmetry breaking in van der Waals crystals that relies on the spontaneous incorporation of stacking faults in a nonpolar bulk layer sequence. The concept is realized in nanowires consisting of Se-rich group IV monochalcogenide (GeSe1–xSₓ) alloys, obtained by vapor–liquid–solid growth. The single crystalline wires adopt a layered structure in which the nonpolar A-B bulk stacking along the nanowire axis is interrupted by single-layer stacking faults with local A-A′ stacking. Density functional theory explains this behavior by a reduced stacking fault formation energy in GeSe (or Se-rich GeSe1–xSₓ alloys). Computations demonstrate that, similar to monochalcogenide monolayers, the inserted A-layers should show a spontaneous electric polarization with a switching barrier consistent with a Curie temperature above room temperature. Second-harmonic generation signals are consistent with a variable density of stacking faults along the wires. Our results point to possible routes for designing ferroelectrics via the layer stacking in van der Waals crystals.

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Series: ACS nano
ISSN: 1936-0851
ISSN-E: 1936-086X
ISSN-L: 1936-0851
Volume: 16
Issue: 12
Pages: 21199 - 21207
DOI: 10.1021/acsnano.2c09172
Type of Publication: A1 Journal article – refereed
Field of Science: 116 Chemical sciences
221 Nanotechnology
Funding: This work was supported by the National Science Foundation, Division of Materials Research, Solid State and Materials Chemistry Program under Grant No. DMR-1904843. EDS measurements were performed in the Nebraska Nanoscale Facility: National Nanotechnology Coordinated Infrastructure and the Nebraska Center for Materials and Nanoscience, which are supported by the National Science Foundation under Award ECCS: 2025298, and the Nebraska Research Initiative. SHG measurements and aberration-corrected STEM imaging were supported by the Center for Nanophase Materials Sciences (CNMS), which is a US Department of Energy, Office of Science User Facility at Oak Ridge National Laboratory.
Copyright information: This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS Nano, copyright © 2022 American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see