Ferroelectricity at two dimensional limit

Ferroelectric material featuring its bi-stable states which can be switched by external electric field, has shown potential applications in nonvolatile memory, and neuromorphic computing. For the conventional oxide ferroelectric materials, especially whose thickness comes to a few unit cells, the notable depolarization effect and intrinsic size effect dominate, leading to the vanishing of the ferroelectric polarization. The rising of two-dimensional van der Waals materials provide a new opportunity for ferroelectricity study. Here, we reported new ferroelectricity discovered at the van der Waals interface of 2D materials. We observed anomalous intermediate polarization states in the multilayer 3R MoS2, with a proposed layer-by-layer switching model for polarization swithcing. We also found the extraordinary fatigue-free nature in 3R MoS₂ sliding ferroelectricity. The extraordinary physical properties of sliding ferroelectricity highlight the potential of 2D ferroelectric materials for new concept device applications.

Reference:

1. Peng Meng, Fucai Liu, et al., “Sliding induced multiple polarization states in two-dimensional ferroelectrics”, Nature Commun., 13, 7696 (2022).
2. Renji Bian, Fucai Liu, et al., “High-Performance Sliding Ferroelectric Transistor Based on Schottky Barrier Tuning”, Nano Lett., 23, 4595 (2023).
3. Renji Bian, Fucai Liu, et al., Developing fatigue-resistant ferroelectrics using interlayer sliding switching, Science DOI: 10.1126/science.ado1744, (2024).
4. Fucai Liu, et al., Room-temperature ferroelectricity in atomically thin CuInP₂S_6, Nature Commun. 7, 12357 (2016)