Electronic Transport and Mechanical Properties of Phosphorus- and Phosphorus-Nitrogen-Doped Carbon Nanotubes

We present a density functional theory study of the electronic structure, quantum transport and mechanical properties of recently synthesized phosphorus (P) and phosphorus-nitrogen (PN) doped single-walled carbon nanotubes. The results demonstrate that substitutional P and PN doping creates localized electronic states that modify the electron transport properties by acting as scattering centers. Nonetheless, for low doping concentrations (1 doping site per similar to 200 atoms), the quantum conductance for metallic nanotubes is found to be only slightly reduced. The substitutional doping also alters the mechanical strength, leading to a 50% reduction in the elongation upon fracture, while Young's modulus remains approximately unchanged. Overall, the PN- and P-doped nanotubes display promising properties for components in composite materials and, in particular, for fast response and ultra sensitive sensors operating at the molecular level.