Fig. 10: The atomic lattice, exchange coupling and RMCD signal of Fe₃GeTe₂.

The atomic lattice of bulk Fe₃GeTe₂ is depicted in Side view (a) and middle top views (b) showcasing its crystal unit cell marked by dashed rectangular and rhombic shapes¹²⁶. c The schematic diagram illustrates the exchange coupling in Fe₃GeTe₂¹⁰⁸. d Remanent RMCD signal is plotted as a function of temperature across a series of selected few-layer flakes (1 L, monolayer; 2 L, bilayer; 3 L, trilayer; 4 L, four layers; 5 L, five layer); The derived values of the exponent β are depicted as a function of thickness in the inset, revealing a dimensional transition from 3D to 2D Ising ferromagnetism¹¹⁷. The figure a and b are reprinted with permission from ref. ¹²⁶ Copyright 2019 by the American Chemical Society. The figure c is reprinted with permission from ref. ¹⁰⁸ Copyright 2021 AIP Publishing LLC. The figure d is reprinted with permission from ref. ¹¹⁷ Copyright 2018 by the Springer Nature.