Basis-set choice for DFT/NEGF simulations of carbon nanotubes
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- Abadir, G.B., Walus, K. & Pulfrey, D.L. J Comput Electron (2009) 8: 1. doi:10.1007/s10825-009-0263-5
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We investigate the effect of the choice of the basis set on the results of ab initio (density functional theory/non-equilibrium Green’s function) calculations of the bandgap of semiconducting carbon nanotubes, and near-zero-bias conductance of metallic carbon nanotubes. Both ideal and deformed carbon nanotubes are studied, as well as nanotubes with an adsorbed biomolecule. The results show that the near-zero-bias conductance of armchair nanotubes can be calculated accurately with a minimal basis set, with the exception of the (2,2) tube, where a polarized basis set is necessary to accurately predict the metallic behaviour of this tube. For zigzag tubes, a double-zeta polarized basis set is in general required for accuracy in bandgap and near-zero-bias conductance calculations.