Prediction of intrinsic two-dimensional ferroelectrics in In2Se3 and other III2-VI3 van der Waals materials

TLDR

Interest in 2D van der Waals materials has surged, yet ferroelectricity has rarely been observed in them. The study uses first‑principles calculations to identify In₂Se₃ and related III₂‑VI₃ van der Waals materials that exhibit room‑temperature ferroelectricity with reversible out‑of‑plane and in‑plane polarization. The authors demonstrate device potential by modeling In₂Se₃/graphene heterostructures with tunable Schottky barriers and In₂Se₃/WSe₂ heterostructures with significant band‑gap reduction. These results suggest that such 2D ferroelectric materials can greatly expand the tunability of van der Waals heterostructures for diverse applications.

Abstract

Abstract Interest in two-dimensional (2D) van der Waals materials has grown rapidly across multiple scientific and engineering disciplines in recent years. However, ferroelectricity, the presence of a spontaneous electric polarization, which is important in many practical applications, has rarely been reported in such materials so far. Here we employ first-principles calculations to discover a branch of the 2D materials family, based on In 2 Se 3 and other III 2 -VI 3 van der Waals materials, that exhibits room-temperature ferroelectricity with reversible spontaneous electric polarization in both out-of-plane and in-plane orientations. The device potential of these 2D ferroelectric materials is further demonstrated using the examples of van der Waals heterostructures of In 2 Se 3 /graphene, exhibiting a tunable Schottky barrier, and In 2 Se 3 /WSe 2 , showing a significant band gap reduction in the combined system. These findings promise to substantially broaden the tunability of van der Waals heterostructures for a wide range of applications.