Coexisting Ferroelectric and Ferroelastic Orders in Rare 3D Homochiral Hybrid Bimetal Halides

Molecular multiferroics that simultaneously possess ferroelectric and ferroelastic orders have sparked growing interest due to their promising uses in shape memory devices, actuators, and sensors. However, it is still a great challenge to effectively explore new molecular multiferroic materials with multiple functionalities. Herein, by introducing homochiral molecules as polar groups, we synthesized a new three-dimensional (3D) bimetal halide multiferroic (R3HP)(2)RbBiBr6(1; R3HP = R-3-hydroxypyrrolidinium). Crystal 1 adopts a mixed face- and corner-sharing Rb-I/Bi-III-centered 4-connected Ion topology with a Schlafli symbol of 6(6). A distinct symmetry breaking with the 2F1 species leads to the emergence of ferroelasticity and biaxial ferroelectricity. Such a 3D homochiral bimetal halide combined with ferroelec-tricity and ferroelasticity is unprecedented. Moreover, 1 exhibits fascinating circularly polarized luminescence and semiconducting properties. This finding signifies an important step toward exploring new hybrid molecular multiferroic materials with the coexistence of ferroelectricity and ferroelasticity and inspires their future multifunctional applications.

Automated summary

The study successfully synthesized a new three-dimensional bimetal halide multiferroic material by introducing homochiral molecules as polar groups, which exhibits both ferroelectric and ferroelastic properties. This discovery represents an important step towards exploring new hybrid molecular multiferroic materials with the coexistence of ferroelectricity and ferroelasticity for future multifunctional applications.