Vibrational properties of single-wall BC3 nanotubes

The phonon dispersions of single-wall BC3 nanotubes with any chirality are calculated within a symmetry-based force constant model of the lattice dynamics. Based on the non-symmorphic symmetry group of the BC3 tubes, the symmetries and number of the Raman- and infrared-active modes at Γ point of the one-dimensional Brillouin zone are given. The neighbor atom–atomic interaction force constants are recalculated by fitting them to the experimental phonon energy-dispersion curves of honeycomb BC3 sheet. The frequencies of the optically active modes are presented as the function of diameters and chiralities for BC3 tubes. The obtained phonon density-of-states spectra, phonon dispersion relations, and vibrational patterns of the zone-center phonons are presented and discussed in detail. The calculated frequencies of infrared-active modes are compared with the experimental values reported in the literature. The results provide comprehensive information about the vibrational properties of the BC3 tubes and shed light on the interpretation of Raman scattering and infrared spectroscopies.