Photoemission spectroscopy on single-wall carbon nanotubes

One-dimensional nature of single-wall carbon nanotubes (SWNTs) has been investigated by the photoemission spectroscopy on SWNT samples with different diameters. We successfully observe peak structures that arise from one-dimensional van Hove singularities. The spectral function and the intensity at the Fermi level both exhibit power-law behavior with almost identical exponents, which indicates that the metallic SWNTs are regarded as ideal one-dimensional systems