Structure and electronic properties of potassium-doped single-wall carbon nanotubes

The structure and electronic properties of potassium-doped single-wall carbon nanotubes have been studied by conduction electron spin resonance, conductivity (σ), and x-ray diffraction (XRD), using in situ electrochemical methods. The spin susceptibility χP of the K-saturated phase is independent of temperature; a lower bound is 5×10^-8emu/g. At 300 K both σ and χP increase monotonically and reversibly with K/C. The spin relaxation rate and g factor do not change with doping, and XRD reveals an irreversible loss of crystallinity upon doping. We propose an inhomogeneous doping model to explain these results.