Coulomb Blockade Regime of a Single-Wall Nanotube

TL;DR

This paper models a half-filled single-wall carbon nanotube with unscreened Coulomb interactions, simplifying excitation spectrum calculations, analyzing phase diagrams, and exploring superconducting fluctuations upon doping.

Contribution

It introduces an adiabatic approximation for the Coulomb interaction in nanotubes, enabling detailed spectral and phase analysis at half filling and with doping effects.

Findings

Adiabatic approximation simplifies excitation spectrum calculations.

Multiple phases with strong superconducting fluctuations emerge upon doping.

Detailed phase diagram at half filling is provided.

Abstract

A model of carbon nanotube at half filling is studied. The Coulomb interaction is assumed to be unscreened. It is shown that this allows to develop the adiabatic approximation which leads to considerable simplifications in calculations of the excitation spectrum. We give a detailed analysis of the spectrum and the phase diagram at half filling and discuss effects of small doping. At small doping several phases develop strong superconducting fluctuations corresponding to various types of pairing.