Electronic structures and transport properties of carbon nanotube

• Published in: Synthetic metals 2001-02, Vol.117 (1), p.61-65
• Main Authors: Yamabe, Tokio, Imade, Masahiro, Tanaka, Motoki, Sato, Thohru
• Format: Article
• Language: English
• Subjects: Carbon nanotube; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electron states and collective excitations in thin films, multilayers, quantum wells, mesoscopic and nanoscale systems; Electronic structure; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Electronic structure of nanoscale materials: clusters, nanoparticles, nanotubes, and nanocrystals; Exact sciences and technology; Physics; Porous nanotube; Tight-binding approximation
• ISSN: 0379-6779; 1879-3290
• DOI: 10.1016/S0379-6779(00)00539-7

The electronic structure of carbon nanotube (CN) (5, 5) with a finite length is studied on the basis of Hückel molecular orbital (HMO) method. Highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) gap oscillates and decreases as the length l of tube increases, where l is the number of cis-polyene rings of the circumference of CN. For tube (5, 5, l) without a cap the gap vanishes at l=3 n+1, where n is a positive integer. On the other hand, the minimum appears at l=3 n for capped tube (5, 5, l). The band gap oscillates with the periodicity of 3 for either capped one or one without a cap. Such behaviors are similar to the one-dimensional (1-D) graphite systems starting from polyphenanthrene. The electronic structures of porous CNs, nanotubes perforated periodically on the cylindrical surface, are studied on the basis of the tight-binding model within the Hückel approximation. Depending on the pitch and the helicity, various band structures appear in porous nanotube with two atoms taken away from the unit cell. Completely flat band also appear in some cases. In those systems flat band ferromagnetism could be expected. Perforation enables us to control the electronic structure of nanotube.