ABSTRACT Multiferroic materials possess diverse functionalities owing to cross‐field responsive capabilities. Integrating these responses with thermally triggered macroscopic shape changes will add a new dimension for multiferroic materials to satisfy the requirement for next‐generation multi‐responsive materials. Here we report a pair of ferroelectric and ferroelastic 1D hybrid metal halides ( R / S ‐3‐HOPD)PbBr 3 (3‐HOPD = 3‐hydroxypiperidinium). The crystals undergo a ferroic structural phase transition at 340 K. The synergistic cation order‐disorder transition and relative displacements of the anionic chains result in a b ‐axis contraction by 18.4% and a c ‐axis expansion by 26.6%, leading to a striking anisotropic deformation of the crystal. Meanwhile, the chiral structure and semiconducting metal‐halide skeleton endow the crystals with chiroptoelectronic functions. This work demonstrates how thermally triggered large anisotropic actuation is integrated into multiferroic crystals, expanding the dimensions of multifunctional stimuli‐responsive materials.
Chai et al. (Tue,) studied this question.