Fig. 3: Zigzag AFM order and spin reorientation transition in ML CrTe2.
a Perspective view of the CrTe2 ML in the zigzag AFM order. Green and red arrows represent the magnetisation directions of Cr atoms. Spin density contours of the selected Te atoms are plotted with an isosurface value of 0.001 e/Bohr3, where the red (green) contours denote the spin-up (spin-down). b Top view of the CrTe2 ML in the zigzag order, superimposed on the DFT-simulated SPSTM image (top) and the spin density contours of the Te atoms (bottom). c Magnetisation axes in the MAE calculation. x, y and z axes correspond to the directions of the lattice vectors. A Cr-Te plane is marked with a red rectangular. d Angular dependence of the calculated MAE. Here, θ and ϕ correspond to the angles between the magnetisation direction and the z and x axes, respectively. A step size of 10° is used in our calculations. The total energy of the Cr moment oriented to the Oo direction was chosen as the zero-energy reference. e Schematics showing magnetic moments, M1 and M2, of two adjacent Cr coupled antiferromagnetically, which are decomposed along the z and y axes (dashed arrows). f, g Evolution of the z-component (f) and y-component (g) of the magnetic moments under a vertical field. h–j Schematics of the SPSTM measurement configurations under different magnetic field directions. The ML CrTe2 is viewed along the black arrow in (a). The tip magnetisation direction is represented with blue arrows. Magnetisation directions of the Cr moment and the Te-px/y orbitals are marked.
