Fig. 1: Characterization of CuCrP2S6.
From: High-performance van der Waals antiferroelectric CuCrP2S6-based memristors
a Crystal structure along [001]. b Top panel: X-ray diffraction of CuCrP2S6. Inset: the optical image of the as-grown crystal. Grid size: 1 mm × 1 mm. Bottom panel: Raman spectrum of CuCrP2S6. c Top panels: piezoresponse phase image with a written box-in-box pattern before and after the 1-day relaxation. Relaxed parts are marked by black dashed lines. Scan size: 6 μm × 6 μm. Bottom panel: PFM amplitude (red) and phase (blue) hysteresis loops for a 10 nm-thick CuCrP2S6 flake. d Cross-sectional crystal structures viewed from a-axis in the antiferroelectric phase and ferroelectric phase with polarization directions. e Polar plot of SHG intensity for poled ferroelectric CuCrP2S6 flakes. f P–E hysteresis loops measured on a CuCrP2S6 ferroelectric capacitor. Test frequency: 100 Hz. g Temperature-dependent SHG intensity measurements. h SHG intensity drops at around 470 K. i Temperature-dependent dielectric properties of CuCrP2S6 measured at 20, 50, 100, 200, and 500 kHz.
