Fig. 1: Exfoliation of the non-van der Waals CrTe crystals by CVD-assisted ultrasonication. | Nature Communications

Fig. 1: Exfoliation of the non-van der Waals CrTe crystals by CVD-assisted ultrasonication.

From: Strong intrinsic room-temperature ferromagnetism in freestanding non-van der Waals ultrathin 2D crystals

Fig. 1

a Unit cell of NiAs-tape CrTe. The purple and brown balls represent Cr and Te atoms, respectively. b–e The surface structures and calculated exfoliation energies Eex (in meV/Å2) of four CrTe crystal faces: b (002), 37.87 meV/Å2; c (100), 130.01 meV/Å2; d (101), 77.31 meV/Å2; and e (110) 50.25 meV/Å2. The green frames in (b–e) denote the range of unit cell. f Mechanism diagram of the cleavage direction for CrTe crystal. g A (002) face exposed bulk CrTe crystal on a SiO2/Si substrate that been mechanically exfoliated easily by a Scotch tape, indicating a small cleavage energy of (002) face. h–j AFM images for mono-UC, bi-UC, and tri-UC 2D CrTe crystals obtained by CVD-assisted ultrasonication with different thicknesses of 0.8 nm (mono-UC), 2 nm (bi-UC), and 3 nm (tri-UC).

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