Fig. 2: Multidomain and DW structure in β’-In2Se3.
From: Two-dimensional ferroelasticity in van der Waals β’-In2Se3
a, b Atomic-resolution ADF-STEM images of 120° and 60° DWs in 2H β’-In2Se3, revealing the unchanged basic structure but the switch of the nanostripe directions across the coherent DWs. c, d SAED patterns of the 120° and 60° DWs. Diffraction spots not on the twin axes show ‘split spots’ as magnified in the top-right inset of d. e Horizontal lattice spacing (as defined in the bottom-left inset) mapped around the 60° DW shown in b, reflecting lattice dilation along the nanostripes. f Schematic of the 60° DW structure based on SAED pattern in d, which can explain the atomic structure and lattice distortion imaged in b and e. The original lattice without twinning is drawn in dashed thin blue lines, which reveal a deviation angle δ that matches the separation angle of diffraction spots in d. The antiparallel polarizations of neighboring nanostripes are indicated by blue/orange arrows in a, b and f.
