title: Room-temperature ferroelectricity in CuInP2S6 ultrathin flakes.
abstract: Two-dimensional (2D) materials have emerged as promising candidates for various optoelectronic applications based on their diverse electronic properties, ranging from insulating to superconducting. However, cooperative phenomena such as ferroelectricity in the 2D limit have not been well explored. Here, we report room-temperature ferroelectricity in 2D CuInP2S6 (CIPS) with a transition temperature of ∼320 K. Switchable polarization is observed in thin CIPS of ∼4 nm. To demonstrate the potential of this 2D ferroelectric material, we prepare a van der Waals (vdW) ferroelectric diode formed by CIPS/Si heterostructure, which shows good memory behaviour with on/off ratio of ∼100. The addition of ferroelectricity to the 2D family opens up possibilities for numerous novel applications, including sensors, actuators, non-volatile memory devices, and various vdW heterostructures based on 2D ferroelectricity.
authors: Centre for Programmed Materials, School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore.
authors: Fucai
authors: F
authors: Liu
authors: School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore.
authors: Lu
authors: 0000-0003-3058-2884
authors: L
authors: You
authors: Department of Physics, University of Washington, Seattle, Washington 98195, USA.
authors: Kyle L
authors: KL
authors: Seyler
authors: School of Civil Engineering, Hefei University of Technology, Hefei 230009, China.
authors: Xiaobao
authors: X
authors: Li
authors: Centre for Programmed Materials, School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore.
authors: Peng
authors: P
authors: Yu
authors: Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee 37235, USA.|Materials Science &Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
authors: Junhao
authors: J
authors: Lin
authors: Centre for Programmed Materials, School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore.
authors: Xuewen
authors: X
authors: Wang
authors: Centre for Programmed Materials, School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore.
authors: Jiadong
authors: J
authors: Zhou
authors: Centre for Programmed Materials, School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore.
authors: Hong
authors: H
authors: Wang
authors: Centre for Programmed Materials, School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore.
authors: Haiyong
authors: H
authors: He
authors: Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee 37235, USA.|Materials Science &Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
authors: Sokrates T
authors: 0000-0002-2963-7545
authors: ST
authors: Pantelides
authors: Materials Science &Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
authors: Wu
authors: 0000-0002-6803-1095
authors: W
authors: Zhou
authors: Department of Mechanical Engineering, University of Houston, Houston, Texas 77204, USA.
authors: Pradeep
authors: P
authors: Sharma
authors: Department of Physics, University of Washington, Seattle, Washington 98195, USA.
authors: Xiaodong
authors: 0000-0003-0348-2095
authors: X
authors: Xu
authors: Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005, USA.
authors: Pulickel M
authors: PM
authors: Ajayan
authors: School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore.
authors: Junling
authors: 0000-0003-3663-7081
authors: J
authors: Wang
authors: Centre for Programmed Materials, School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore.|NOVITAS, Nanoelectronics Centre of Excellence, School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798, Singapore.|CINTRA CNRS/NTU/THALES, UMI 3288, Research Techno Plaza, 50 Nanyang Drive, Border X Block, Level 6, Singapore 637553, Singapore.
authors: Zheng
authors: Z
authors: Liu