Giant Modulation of the Second Harmonic Generation by Magnetoelectricity in two Dimensional Multiferroic CuCrP 2 S 6.

Multiferroic materials have attracted considerable attention owing to their unique magnetoelectric or magnetooptical properties. Recent discovery of few-layer van der Waals multiferroic crystals provide a new research direction of controlling the multiferroic properties in the atomic layer limit. However, research on few-layer multiferroic crystals is limited and the effect of thickness dependent symmetries on those properties are less explored. In this study, we investigated the symmetries and magnetoelectric responses of van der Waals multiferroic CuCrP 2 S 6 by optical second harmonic generation (SHG). Structural and magnetic phase transitions were successfully probed by the temperature-dependent SHG signals, revealing significant changes by applying the magnetic field reflecting the magnetoelectric effect. Moreover, we found that symmetries and resultant magnetoelectric responses can be modulated by the number of layers. These results offer a new principle of controlling the multiferroicity and indicate two-dimensional vdW multiferroic material is a promising building block for functional nanodevices. This article is protected by copyright. All rights reserved.