Localized valence states characteristics and work function of single-walled carbon nanotubes: A first-principles study

The localized valence states characteristics of single-walled carbon nanotubes (SWNT’s) are described by virtue of the discrete energy levels within first-principles calculations. We find that the contributions of the localized valence states to field emission are sensitively dependent on their spatial orientations and deduce that the electron emission in one individual SWNT is not a continuum as in conventional metallic emitters. The work function of SWNT’s is defined and calculated within the framework of the linear combination of atomic orbitals for the molecular orbital cluster method, and its localized features are discussed.