Analysis of a capped carbon nanotube by linear-scaling density-functional theory

Highlights: • A capped (5,5) carbon nanotube has been analysed by the linear-scaling DFT code ONETEP. • The charge distribution varies very little with external fields, showing screening. • The calculation reports details of individual Kohn-Sham orbitals. • The highest occupied orbital and its distribution change with applied field. • The work function is part of an energy change from the cores, due to many-electron effects. -- Abstract: The apex region of a capped (5,5) carbon nanotube (CNT) has been modelled with the DFT package ONETEP, using boundary conditions provided by a classical calculation with a conducting surface in place of the CNT. Results from the DFT solution include the Fermi level and the physical distribution and energies of individual orbitals for the CNT tip. Application of an external electric field changes the orbital number of the highest occupied molecular orbital (HOMO) and consequently changes its distribution on the CNT.