Coherent transport in SWCNTs with spin-orbit coupling

Coherent transport in single wall carbon nanotubes in the presence of spin-orbit coupling is investigated theoretically. Reflectionless contacts are used for probing the electronic transport through infinite SWCNTs for different spin polarizations. It is shown that the spin-orbit interactions give rise to flipping of the electron spin states for sufficiently long CNTs. Spin flip processes are clearly distinguished in the lowest conduction mode, while mode mixing in different conduction modes obscures the spin flipping length for higher energies of the incoming electrons. Spin flipping lengths are also calculated for single mode transmissions with estimated spin-orbit coupling parameters. Several considerations for the accurate measurement of the spin relaxation lengths (L_C) and the spin-orbit coupling parameters are discussed.