Coulomb blockade without potential barriers
Institut de Physique et Chimie des Matériaux de Strasbourg (UMR 7504 ULP-CNRS.), BP 43, 23 rue du Lœss, 67034 Strasbourg Cedex 2, France
Revised: 30 March 2006
Published online: 1 June 2006
We study transport through a strongly correlated quantum dot and show that Coulomb blockade can appear even in the presence of perfect contacts. This conclusion arises from numerical calculations of the conductance for a microscopic model of spinless fermions in an interacting chain connected to each lead via a completely open channel. The dependence of the conductance on the gate voltage shows well defined Coulomb blockade peaks which are sharpened as the interaction strength is increased. Our numerics is based on the embedding method and the DMRG algorithm. We explain the emergence of Coulomb blockade with perfect contacts by a reduction of the effective coupling matrix elements between many-body states corresponding to successive particle numbers in the interacting region. A perturbative approach, valid in the strong interaction limit, yields an analytic expression for the interaction-induced suppression of the conductance in the Coulomb blockade regime.
PACS: 73.23.Hk – Coulomb blockade; single-electron tunneling / 73.23.-b – Electronic transport in mesoscopic systems / 71.27.+a – Strongly correlated electron systems; heavy fermions
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2006