Linear and nonlinear transport across carbon nanotube quantum dots

Leonhard Mayrhofer (1) , Milena Grifoni (1)

1 Institut für theoretische Physik, Universität Regensburg

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.

Domaines: Systèmes mésoscopiques et effet Hall quantique [cond-mat.mes-hall]; Electrons fortement corrélés [cond-mat.str-el]

Leonhard Mayrhofer, Milena Grifoni. Linear and nonlinear transport across carbon nanotube quantum dots. The European Physical Journal B: Condensed Matter and Complex Systems, 2007, 56 (2), pp.107. ⟨10.1140/epjb/e2007-00097-3⟩. ⟨hal-00119840v2⟩