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

TL;DR

This paper investigates how flexoelectric coupling causes bend elasticity softening, leading to spontaneous chiral symmetry breaking in polar fluids with achiral molecules, revealing a fundamental mechanism for heliconical structure formation.

Contribution

It identifies flexoelectric coupling as the key mechanism behind bend elasticity softening and chiral symmetry breaking in polar fluids, linking molecular shape to macroscopic behavior.

Findings

Flexoelectric coupling causes bend elasticity softening.

Softening occurs near phase transition.

Chiral symmetry breaking emerges spontaneously.

Abstract

The origin of recently observed spontaneous chiral symmetry breaking in polar fluids is an unsolved problem, and poses fundamental questions as to how heliconical structures emerge in systems composed of achiral molecules. We report on the softening of bend elasticity close to such phase transition, showing that flexoelectric coupling between the electric polarization and the bend deformation is the responsible mechanism, presumably arising from the bent shape of the constituent highly polar molecules.