Physical Review B
Strongly interacting Luttinger liquid states as those inherent in carbon nanotubes
Igor N. Karnaukhov, Victor I. Kolomytsev, Cees G. H. Diks
Abstract
The electronic transport properties of single-walled nanotubes (SWNTs) are characterized by the critical exponent $\ensuremath{\Theta}$, describing the behavior of the single-particle spectral function near the Fermi energy as $\ensuremath{\rho}(\ensuremath{\omega})\ensuremath{\propto}{\ensuremath{\mid}\ensuremath{\omega}\ensuremath{\mid}}^{\ensuremath{\Theta}}$. Experimentally obtained $\ensuremath{\Theta}$ values have been reported in the range of 0.43--0.48 for metallic SWNTs. However, these values are much larger than the theoretical upper limit of the exponent, ${\ensuremath{\Theta}}_{\mathrm{max}}=1∕8$, for the Hubbard model. Here, we show that the observed electronic transport properties can be explained by taking into account a specific hard-core Coulomb interaction. For a many-body system with a hard-core potential, we analytically calculate the critical exponents using the Bethe ansatz and conformal field theory. We find strongly interacting Luttinger liquid states that are characterized by large $\ensuremath{\Theta}$ values, consistent with the empirical results, suggesting that these states are actually realized in metallic SWNTs and organic conductors.