Fig. 1: Structure and exfoliation of CsV3Sb5 thin flakes.
a Crystal structure of CsV3Sb5. b Illustration of the exfoliation of thin flakes and the loss of surface Cs. The schematic structure of an eight-layer thin flake without surface Cs can be found in Supplementary Fig. 3b. c Low-magnification STEM image of the exfoliated flakes. The determination of the thickness can be found in Supplementary Note 2. The selected area electron diffraction (SAED) of the white broken line area (4 layers) is shown in the inset. d Annular bright-field (ABF)-STEM image of CsV3Sb5 with the thickness of 8 layers. We use 4 L for 4 layers as a shorthand and the same goes for other thicknesses.
