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Flexoelectricity-driven softening of bend elasticity leads to spontaneous chiral symmetry breaking in a polar fluid

Aitor Erkoreka1, Josu Martinez-Perdiguero1, Luka Cmok2,3, Ema Hanžel2,3, Jordan Hobbs4, Calum J. Gibb5, Richard J. Mandle4,5, Nerea Sebastián2, and Alenka Mertelj2,*

  • *Contact author: alenka.mertelj@ijs.si
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Phys. Rev. E 114, 045407 – Published 21 October, 2026

DOI: https://doi.org/10.1103/m11g-4rj9

Abstract

The origin of the recently observed spontaneous chiral symmetry breaking in polar fluids composed of achiral molecules is an unsolved problem, raising fundamental questions about how heliconical structures emerge in such systems. Here, we investigate the pretransitional fluctuations leading to the formation of the spontaneously chiral twist-bend ferroelectric nematic phase using dielectric spectroscopy, light scattering, and small-angle x-ray scattering. We observe simultaneous softening of the bend elastic constant and the emergence of a collective dielectric mode on approaching the transition. By developing a theoretical model, we show that these phenomena are signatures of a flexoelectricity-driven transition arising from the coupling between electric polarization and bend deformation.

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Outline

Information

Phys. Rev. E 114, 045407– Published 21 October, 2026
  • Received 19 February 2026
  • Accepted 17 September 2026
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

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