Spectroscopy of phonon modes of a single-wall armchair carbon nanotube using measurements of nonlinear conductance: Theory

We present a theoretical study of the differential conductance of a finite-length armchair single-wall carbon nanotube in the presence of electron-phonon interaction by employing a perturbative approach. It is shown that the nonlinear conductance measurement can be regarded as a novel method for detecting longitudinal optical phonon modes, which have non-negligible electron-phonon coupling in a proper applied bias range. Furthermore, it is found that at high temperatures, differential conductance depends on temperature, while this dependence is smeared out as temperature decreases.