Effective low-energy theory of superconductivity in carbon nanotube ropes

De Martino, A. & Egger, R. (2004). Effective low-energy theory of superconductivity in carbon nanotube ropes. Physical Review B (PRB), 70, doi: 10.1103/PhysRevB.70.014508

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Abstract

We derive and analyze the low-energy theory of superconductivity in carbon nanotube ropes. A rope is modelled as an array of metallic nanotubes, taking into account phonon-mediated as well as Coulomb interactions, and arbitrary Cooper pair hopping amplitudes (Josephson couplings) between different tubes. We use a systematic cumulant expansion to construct the Ginzburg-Landau action including quantum fluctuations. The regime of validity is carefully established, and the effect of phase slips is assessed. Quantum phase slips are shown to cause a depression of the critical temperature Tc below the mean-field value, and a temperature-dependent resistance below Tc. We compare our theoretical results to recent experimental data of Kasumov {\sl et al.} [Phys. Rev. B {\bf 68}, 214521 (2003)] for the sub-$T_c$ resistance, and find good agreement with only one free fit parameter. Ropes of nanotubes therefore represent superconductors in the one-dimensional few-channel limit.

Item Type: Article 11 pages, 4 figures Q Science > QC Physics School of Engineering & Mathematical Sciences > Department of Mathematical Science Author http://openaccess.city.ac.uk/id/eprint/1667