Effect of Torsional Deformations on the Spin States of Carbon Nanotubes with Metallic Conductivity.

The formation of spin levels upon torsional deformation of nonchiral (n, n) carbon nanotubes has been theoretically studied. In the absence of mechanical deformation, nanotubes have inversion symmetry and a metallic band structure with a spin-degenerate state near the Fermi level. The twisting deformation breaks the inversion symmetry, so that the tube becomes chiral. As a result, due to the Rashba effect, the degeneracy of the levels is completely lifted and spin gaps are formed between the bands of predominantly α and β types. [ABSTRACT FROM AUTHOR]