Curvature effects on the structural, electronic and optical properties of isolated single-walled carbon nanotubes within a symmetry-adapted non-orthogonal tight-binding model

摘要: The effects of curvature on the structure, electronic and optical properties isolated single-walled carbon nanotubes are studied within a symmetry-adapted non-orthogonal tight-binding model using 2s 2p electrons carbon. scheme allows reducing matrix eigenvalue problem for to diagonalization 8×8 matrices any nanotube type. Due this simplification, band structure with very large number atoms in unit cell can be calculated. Using model, 187 small- moderate-radius is optimized. It found that deviations optimized from non-optimized one tube radii smaller than 5 A. dielectric function 101 transition energies these derived plotted versus radius. shown structural optimization introduces small changes obtained model. agree well available ab initio data few types. On other hand, results former deviate widely those used characterization π-band especially small-radius tubes. assignment absorption spectra selection types which Raman scattering resonant.