Sliding-induced high polarization and multistate ferroelectricity in a van der Waals BP/BP/GaN/GaN heterostructure

Abstract

Sliding ferroelectricity has attracted significant research interest due to its ultralow switching barrier and its presence in diverse systems, such as van der Waals (vdW) layered materials. Its polarization is strongly dependent on the material type, layer number, and stacking sequence. In this work, we investigate 27 asymmetric stacking configurations in a four-layer BP/BP/GaN/GaN vdW heterostructure using first-principles calculations. We find that this heterostructure not only retains a low switching barrier comparable to that of the corresponding homogeneous structure but also exhibits a broader range of asymmetric polarization states. Focusing on the four lowest-energy quasi-degenerate states, we explore the layer-selective polarization switching mechanism and the dynamic regulation of the BP/BP/GaN/GaN sliding ferroelectric heterostructure. Our results provide a theoretical basis and design strategy for sliding ferroelectricity in 2D vdW heterostructures.