Two-dimensional ferroelasticity in van der Waals β’-In2Se3

• DOI: 10.1038/s41467-021-23882-7
• Publication Date: 2021-06-16T10:03:04Z
• Authors: Chao Xu; Jianfeng Mao; Xuyun Guo; Shanru Yan; Yancong Chen; Tsz Wing Lo; Changsheng Chen; Dangyuan Lei; Xin Luo; Jianhua Hao; Changxi Zheng; Ye Zhu
• Keywords: Ferroelasticity; Antiferroelectricity; Distortion (music)

Abstract Two-dimensional (2D) materials exhibit remarkable mechanical properties, enabling their applications as flexible and stretchable ultrathin devices. As the origin of several extraordinary behaviors, ferroelasticity has also been predicted theoretically in 2D materials, but so far lacks experimental validation investigation. Here, we present demonstration both exfoliated chemical-vapor-deposited β’ -In 2 Se 3 down to few-layer thickness. We identify quantitatively spontaneous strain originating from in-plane antiferroelectric distortion, using atomic-resolution electron microscopy situ X-ray diffraction. The symmetry-equivalent orientations give rise three domain variants separated by 60° 120° walls (DWs). Mechanical switching between these ferroelastic domains is achieved under ≤0.5% external strain, demonstrating feasibility tailor polar structure well DW patterns through stimuli. detailed mechanism propagation nucleation unraveled, effects 3D stacking on such are discussed. observed here should be widely available with anisotropic lattice including 1T’ transition metal dichalcogenides Peierls distortion ferroelectrics SnTe family, rendering tantalizing potential tune functionalities or engineering.