Figure 5.

Examples of large-area 2D magnets grown by MBE. (a–d) Monolayer CrCl₃ on Graphene/SiC(0001) and (e–g) few-layer Fe₃GeTe₂ on GaAs (111). (a) Schematic crystal structure of CrCl₃/graphene/6H-SiC layers in top-down view and cross-section view. (b) In situ RHEED pattern of the substrate and monolayer CrCl₃ grown by MBE, along Γ–M of graphene (Γ–K of SiC). Streaks from different high-symmetry directions of CrCl₃ are observed, implying a twisted in-plane orientation of the grains. (c) STM topography of a monolayer CrCl₃ grown on graphene/6H-SiC(0001), indicating a homogeneous coverage on long length scales. Inset: A magnified topography image, which reveals the grain boundaries. (d) Atom resolved image of the CrCl₃ lattice featuring a moiré pattern (upper panel) and its Fourier transformed image (lower panel). Panels (a–d) adapted with permission from ref (78). Copyright 2021 AAAS. (e) Crystal structure of Fe₃GeTe₂. (f) RHEED oscillations indicating layer-by-layer growth of Fe₃GeTe₂ (0001) on GaAs (111), and the corresponding electron diffraction pattern (inset). The inferred growth rate is 111 s per monolayer. (g) Transmission electron microscopy of a Fe₃GeTe₂/GaAs cross-section, indicating the (111)/(0002) epitaxial relationship. Panels (e–g) adapted with permission under a Creative Commins CC BY license from ref (99). Copyright 2017 Springer Nature.