Energetics and electronic structures of nitrogen chains encapsulated in zigzag carbon nanotube

Abstract

This article presents first-principles self-consistent-field crystal orbital calculations on the structures and electronic properties for the combined systems made of nitrogen atom chains inserted in zigzag carbon nanotubes (CNTs). We find that the nitrogen chains with the zigzag structure can be well stabilized by the outside CNTs. The molecular dynamics simulations based on density functional with tight binding method confirmed the stability of nitrogen chains under the confined conditions. Thus the zigzag CNTs can be as containers to confine and stabilize the polymeric nitrogen chains. According to the obtained binding energy, (9, 0) tube is the most favorable to filling the nitrogen chain. The combined systems are all metals except the filling into (7, 0) tube, indicating the encapsulation of the nitrogen chain can modulate the electronic properties for the combined systems. The interaction between the nitrogen chain and CNTs is also discussed based on the reduced density gradient, band structures and electronic density difference analysis. It is found that the van der Waals force, charge transfer and orbital interaction are all important for the formation of the combined systems.