Solitons in carbon nanotubes

The symmetries of spontaneous lattice distortions in carbon nanotubes are investigated. When the degeneracy of the ground states remains discrete, there are solitons or domain walls connecting the different symmetry-broken vaccua. These solitons, similarly to the case of polyacetelene, are fractionally charged states. In addition to the topological domain walls, there are polaron states with discrete energies within the energy gap. The energies and shapes of these localized midgap states should be accessible via scanning tunneling microscopy spectroscopy.