Commensurability effect on the electronic structure of carbon nanostructures: Impact on supercell calculations in nanotubes

• Autor(a) principal: Ferreira, M. S.
• Data de Publicação: 2017
• Outros Autores: Rocha, C. G., Lawlor, J. A., Venezuela, P., Amorim, R. G., Rocha, A. R. [UNESP]
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://dx.doi.org/10.1209/0295-5075/117/27005; http://hdl.handle.net/11449/174356

Friedel oscillations are ubiquitous features seen in all impurity-doped metallic structures but in the case of graphene-like materials they are not so evident because the relevant wavelengths are perfectly commensurate with the lattice parameter. Here we demonstrate that this commensurability effect leads to a slow convergence of supercell-based total energy calculations in impurity-doped carbon nanotubes. We derive a mathematically transparent expression for the formation energy and identify a very distinctive dependence on the size of the supercell unit. We make use of this dependence through a simple extrapolation scheme to obtain density functional theory results with accuracy levels that would otherwise require enormously large unit cells.