Dysprosium metal intercalation and deposition experiments provide more information about the bell-shaped-component (BSC). The BSC increases with metal intercalation, because a more uniform interface forms as the metal atoms move between graphene and SiC. These experiments support the conclusion that the BSC originates from electron confinement within a single layer material. This is an unusually strong manifestation of the uncertainty principle in mesoscale experiments.
S. Chen, M. Horn von Hoegen, P. A. Thiel, A. Kaminski, B. Schrunk, T. Speliotis, E. H. Conrad, and M. C. Tringides, J. Phys. Chem. Lett. 11, 21, 8937–8943 (2020) “High Layer Uniformity of Two-Dimensional Materials Demonstrated Surprisingly from Broad Features in Surface Electron Diffraction”