• 文献标题:   Low-energy electron reflectivity from graphene: First-principles computations and approximate models
  • 文献类型:   Article, Proceedings Paper
  • 作  者:   FEENSTRA RM, WIDOM M
  • 作者关键词:   lowenergy electron microscopy, graphene, surface, electron reflectivity
  • 出版物名称:   ULTRAMICROSCOPY
  • ISSN:   0304-3991 EI 1879-2723
  • 通讯作者地址:   Carnegie Mellon Univ
  • 被引频次:   13
  • DOI:   10.1016/j.ultramic.2013.02.011
  • 出版年:   2013

▎ 摘  要

A computational method is developed whereby the reflectivity of low-energy electrons from a surface can be obtained from a first-principles solution of the electronic structure of the system. The method is applied to multilayer graphene. Two bands of reflectivity minima are found, one at 0-8 eV and the other at 14-22 eV above the vacuum level. For a free-standing slab with n layers of graphene, each band contains n-1 zeroes in the reflectivity. Two additional image-potential type states form at the ends of the graphene slab, with energies just below the vacuum level, hence producing a total of 2n states. A tight-binding model is developed, with basis functions localized in the spaces between the graphene planes (and at the ends of the slab). The spectrum of states produced by the tight-binding model is found to be in good agreement with the zeros of reflectivity (i.e. transmission resonances) of the first-principles results. (C) 2013 Elsevier BY. All rights reserved.