The reflectivity of low energy electrons from graphene on copper substrates is studied both experimentally and theoretically. Well-known oscillations in the reflectivity of electrons with energies 0 - 8 eV above the vacuum level are observed in the experiment. These oscillations are reproduced in theory, based on a first-principles density functional description of interlayer states forming for various thicknesses of multilayer graphene. It is demonstrated that n layers of graphene produce a regular series of n-1 minima in the reflectance spectra, together with a possible additional minimum associated with an interlayer state forming between the graphene and the substrate. Both (111) and (001) orientations of the copper substrates are studied. Similarities in their reflectivity spectra arise from the interlayer states, whereas differences are found because of the different Cu band structures along those orientations. Results for graphene on other substrates, including Pt(111) and Ir(111), are also discussed.
@article{arxiv.1303.2904,
title = {Low-Energy Electron Reflectivity of Graphene on Copper and other Substrates},
author = {N. Srivastava and Qin Gao and M. Widom and R. M. Feenstra and Shu Nie and K. F. McCarty and I. V. Vlassiouk},
journal= {arXiv preprint arXiv:1303.2904},
year = {2015}
}
Comments
22 pages, 10 figures in main manuscript; 12 pages, 5 figures in supplemental material; v2, added figs 1 and 8 in main manuscript and S6 in supplemental material, and made minor changes in text; v3, incorporated supplemental material into an Appendix