Phonon-assisted transport through suspended carbon nanotube quantum dots

Motivated by several recent experiments, we investigate phonon-assisted electronic transport through suspended carbon nanotube quantum dots including electron-electron, electron-phonon, and spin-orbit interactions. By effectively decoupling the electron and phonon thermodynamics, we present an explanation for the puzzling thermoinduced vibrational absorption sidebands, as well further predict that these absorption sidebands are obviously diminished in the partially filled Coulomb diamonds due to the destructive superposition of electron and hole states. The spin-orbit coupling is shown to split all phonon-assisted sidebands while the Kramers degeneracy remains. Interestingly, in the strong spin-orbit coupling regime, some split absorption sidebands are suppressed by the Coulomb blockade effect, while all split emission sidebands always survive.