2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/29039Disorder effects on the density of states in carbon nanotubes are analyzed by a tight binding model with Gaussian bond or site disorder. Metallic armchair and semiconducting zigzag nanotubes are investigated. In the strong disorder limit, the conduction and valence band states merge, and a finite density of states appears at the Fermi energy in both of metallic and semiconducting carbon nanotubes. The bond disorder gives rise to a huge density of states at the Fermi energy differently from that of the site disorder case. Consequences for experiments are discussed.Phys. Rev. B: Brief Reports (to be published). Related preprints can be found at http://www.etl.go.jp/~harigaya/NEW.htmlCondensed MatterChemical PhysicsOpticsQuantum Physicstext