Defect-induced multicomponent electron scattering in single-walled carbon nanotubes

We present a detailed comparison between theoretical predictions on electron scattering processes in metallic single-walled carbon nanotubes with defects and experimental data obtained by scanning tunneling spectroscopy of Ar⁺ irradiated nanotubes. To this purpose, we first develop a formalism for studying quantum transport properties of defected nanotubes in the presence of source and drain contacts and a scanning tunneling microscopy tip. The formalism is based on a field theoretical approach describing low-energy electrons. We account for the lack of translational invariance induced by defects within the so-called extended k•p approximation, which allows for multicomponent scattering with new scattering channels that are associated with exchanged momenta larger than the difference between the K points of the nanotube. The theoretical model reproduces the features of the particle-in-a-box-like states observed experimentally. Further, the comparison between theoretical and experimental Fourier-transformed local density of states maps yields clear signatures for intervalley and intravalley electron scattering processes depending on the tube chirality.