https://doi.org/10.1140/epjb/s10051-026-01123-4
Research - Condensed Matter
Janus ZrFX (X = Cl, Br, I) monolayers with giant vertical piezoelectricity exhibiting electronegativity difference ratio effect
1
School of Physics Science and Information Technology, Liaocheng University, 252059, Liaocheng, China
2
School of Chemistry and Chemical Engineering, Liaocheng University, 252059, Liaocheng, China
a
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Received:
21
October
2025
Accepted:
8
January
2026
Published online:
21
January
2026
The advancement of piezoelectric materials is often constrained by insufficient understanding of their internal mechanisms and limited out-of-plane piezoelectric response. In this work, Janus ZrFX (X = Cl, Br, or I) monolayers are proposed, and their stress and strain piezoelectric coefficients are systematically investigated. The structural stability of these monolayers is confirmed through analyses of dynamic, thermodynamic, and mechanical properties. The results reveal that breaking mirror symmetry in these structures leads to remarkable vertical piezoelectricity, with piezoelectric strain coefficients exceeding those of other Janus materials by two to three orders of magnitude. The significant enhancement is explained by Bader charge and electronegativity difference ratios. The larger the electronegativity difference ratio is, the stronger the piezoelectricity will be. Furthermore, the superior vertical piezoelectric performance is associated with strong built-in electric fields and high Born effective charges of halogen atoms, providing deeper insight into the underlying physical origin. Additionally, ZrFX monolayers exhibit an intrinsic coupling between piezoelectricity and carrier transport, where a weaker polarization field correlates with higher hole mobility. This study not only identifies promising candidates for energy conversion and tactile sensing but also lays a theoretical foundation for the design of advanced nanoscale piezoelectric devices.
Supplementary Information The online version contains supplementary material available at https://doi.org/10.1140/epjb/s10051-026-01123-4.
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© The Author(s), under exclusive licence to EDP Sciences, SIF and Springer-Verlag GmbH Germany, part of Springer Nature 2026
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
