Atomic arrangement of van der Waals heterostructures using X-ray scattering and crystal truncation rod analysis

Vanadium diselenide (VSe₂) has intriguing physical properties such as unexpected ferromagnetism at the two-dimensional limit. However, the experimental results for room temperature ferromagnetism are still controversial and depend on the detailed crystal structure and stoichiometry. Here we introduce crystal truncation rod (CTR) analysis to investigate the atomic arrangement of bilayer VSe₂ and bilayer graphene (BLG) heterostructures grown on a 6H–SiC(0001) substrate. Using non-destructive CTR analysis, we were able to obtain electron density profiles and detailed crystal structure of the VSe₂/BLG heterostructures. Specifically, the out-of-plane lattice parameters of each VSe₂ layer were modulated by the interface compared to that of the bulk VSe₂ 1T phase. The atomic arrangement of the VSe₂/BLG heterostructure provides deeper understanding and insight for elucidating the magnetic properties of the van der Waals heterostructure.