Eur. Phys. J. B 56, 107-125 (2007)
https://doi.org/10.1140/epjb/e2007-00097-3

Linear and nonlinear transport across carbon nanotube quantum dots

Theoretische Physik, Universität Regensburg, 93040 Regensburg, Germany

Corresponding author: ^a leonhard.mayrhofer@web.de

Received: 12 December 2006
Revised: 27 February 2007
Published online: 12 April 2007

Abstract

We present a low energy-theory for non-linear transport in finite-size interacting single-wall carbon nanotubes. It is based on a microscopic model for the interacting p_z electrons and successive bosonization. We consider weak coupling to the leads and derive equations of motion for the reduced density matrix. We focus on the case of large-diameter nanotubes where exchange effects can be neglected. In this situation the energy spectrum is highly degenerate. Due to the multiple degeneracy, diagonal as well as off-diagonal (coherences) elements of the density matrix contribute to the nonlinear transport. At low bias, a four-electron periodicity with a characteristic ratio between adjacent peaks is predicted. Our results are in quantitative agreement with recent experiments.