New regime of the Coulomb blockade in quantum dots

TL;DR

This paper investigates how the lack of thermalisation influences Coulomb blockade behavior in quantum dots, revealing new phenomena such as a suppressed Coulomb staircase and an additional conductance peak.

Contribution

It introduces a quantum kinetic equation approach to analyze Coulomb blockade without thermalisation, uncovering novel effects in current-voltage characteristics.

Findings

Coulomb staircase reduces to the first step with asymmetric couplings

An additional peak appears in differential conductance when couplings are similar

Standard thermalized results are recovered in the thermalisation regime

Abstract

We consider how the absence of thermalisation affects the classical Coulomb blockade regime in quantum dots. By solving the quantum kinetic equation in the experimentally accessible regime when the dot has two relevant occupation states, we calculate the current-voltage characteristics for arbitrary coupling to the leads. If the couplings are strongly asymmetric, we have found that the Coulomb staircase practically reduces to the first step independent of the charging energy when the latter is larger than the Fermi energy, while the standard thermalised results are recovered in the opposite case. If the couplings are of the same order, the absence of thermalisation has a new, striking signature - a robust additional peak in the differential conductance.