Electric Field-Controlled Interfacial Polarization Coupling in van der Waals Ferroelectric Heterojunctions

Recent advances in van der Waals (vdW) ferroelectrics have sparked the development of related heterostructures with non-volatile and field-tunable functionalities. In vdW ferroelectric heterojunctions, the interfacial electrical characteristics play a crucial role in determining their performance and functionality. In this study, we explore the interfacial polarization coupling in two-dimensional (2D) ferroelectric heterojunctions by fabricating a graphene/h-BN/CuInP_2S_6/\alpha-In_2Se_3/Au ferroelectric field-effect transistor. By varying the gate electric field, the CuInP_2S_6/\alpha-In_2Se_3 heterojunction displays distinct interfacial polarization coupling states, resulting in significantly different electrical transport behaviors. Under strong gate electric fields, the migration of Cu ions further enhances the interfacial polarization effect, enabling continuous tuning of both the polarization state and carrier concentration in \alpha-In_2Se_3. Our findings offer valuable insights for the development of novel multifunctional devices based on 2D ferroelectric materials.