Coulomb blockade without potential barriers

TL;DR

This paper demonstrates that Coulomb blockade effects can occur without potential barriers in a strongly correlated quantum dot, using numerical methods to analyze conductance behavior in an interacting fermion chain.

Contribution

It shows Coulomb blockade can emerge with perfect contacts due to interaction effects, supported by numerical and analytical approaches.

Findings

Coulomb blockade peaks appear even with perfect contacts.

Interaction strength sharpens Coulomb blockade features.

Analytic expression derived for conductance suppression in strong interactions.

Abstract

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.