Fine structure in the off-resonance conductance of small Coulomb blockade systems

TL;DR

This paper reveals a fine, multiple-peak structure in the off-resonance conductance of Coulomb blockade systems, emphasizing the importance of quantum fluctuations over mean-field models.

Contribution

It introduces a novel explanation for conductance features by considering quantum fluctuations, using an Anderson-like model and a new Green's function calculation method.

Findings

Multiple-peak conductance structure observed

Quantum fluctuations are crucial for understanding conductance

Method applicable to multi-level Coulomb blockade systems

Abstract

We show how a fine, multiple-peak structure can arise in the off-resonance, zero-bias conductance of Coulomb blockade systems. In order to understand how this effect comes about one must abandon the orthodox, mean-field understanding of the Coulomb blockade phenomenon and consider quantum fluctuations in the occupation of the single-particle electronic levels. We illustrate such an effect with a spinless Anderson-like model for multi-level systems and an equation-of-motion method for calculating Green's functions that combines two simple decoupling schemes.