Fig. 5. 2D ferroelasticity in ultrathin β’-In₂Se₃ flakes grown by CVD.

a Polarized-light image showing the presence of domain structure in an as-grown ultrathin flake. b AFM image of the area highlighted by the orange box in a. The inset line profile indicates a thickness of ~6.6 nm. c SAED pattern of an ultrathin β’-In₂Se₃ flake, revealing the preservation of superstructure indicated by the satellite diffraction. d–f Polarized-light images showing ferroelastic domain switching in an ultrathin β’-In₂Se₃ flake upon applying the tensile strain.