CuInP2S6 Room Temperature Layered Ferroelectric

• DOI: 10.1021/acs.nanolett.5b00491
• Publication Date: 2015-05-01T14:24:06Z
• Authors: A. Belianinov; Q. He; A. Dziaugys; P. Maksymovych; E. Eliseev; A. Borisevich; A. Morozovska; J. Banys; Y. Vysochanskii; S. V. Kalinin
• Keywords: 01 natural sciences; 0104 chemical sciences

We explore ferroelectric properties of cleaved 2-D flakes copper indium thiophosphate, CuInP2S6 (CITP), and probe size effects along with limits phase stability, by ambient ultra high vacuum scanning microscopy. CITP belongs to the only material family known display polarization in a van der Waals, layered crystal at room temperature above. Our measurements directly reveal stable, as evidenced domain structures, switchable polarization, hysteresis loops. found that structure thicker than 100 nm is similar bulk surfaces, whereas below 50 disappears. ascribe this behavior well-known instability due depolarization field. Furthermore, switching bias also associated ionic mobility, both macroscopic formation surface damage under tip 4 V—likely reduction. Mobile Cu ions may therefore contribute internal screening mechanisms. The existence stable van-der-Waals naturally points toward new strategies for ultimate scaling polar materials, quasi-2D, single-layer materials advanced nonlinear dielectric are presently not any members growing “graphene family”.