Effect of chemical intercalation on ferroelectricity in van der Waals layered CuInP2S6

Abstract

Chemical intercalation brings about intriguing opportunities to tailor the properties of van der Waals (vdW) layered materials by crafting molecular composite at an atomic scale. Despite a plethora of reports on various materials, the chemical intercalation effect on long-range ferroelectric order remains scarcely explored. Herein, we report the construction of hybrid supercrystal based on a model vdW ferroelectric, CuInP2S6 by molecular intercalation. Although the out-of-plane lattice structure remains commensurate, its ferroelectric polarization is largely destroyed by the chemical intercalation, as confirmed by combined piezoresponse microscopy and Raman spectroscopy. Alternatively, we observed a dipole glass transition at about 280 K by dielectric spectroscopy and correlated it with the Raman analysis. This work highlights the impact of chemical intercalation on collective ferroic orders and paves the routes for creating artificial hybrid crystals by incorporating functional molecules.