Two-instanton approximation to the Coulomb blockade problem

TL;DR

This paper introduces a two-instanton approximation method to analyze the Coulomb blockade in single electron transistors, revealing how bias voltage suppresses oscillations and shifts phase, with detailed temperature and gate voltage dependence.

Contribution

It presents a novel two-instanton approximation approach to the Coulomb blockade problem within the Ambegaokar-Eckern-Schön model, enhancing understanding of conductance oscillations.

Findings

Bias voltage suppresses Coulomb blockade oscillations.

Phase shift in conductance depends on bias voltage.

Temperature and gate voltage influence oscillation behavior.

Abstract

We develop the two-instanton approximation to the current-voltage characteristic of a single electron transistor within the Ambegaokar-Eckern-Sch\"on model. We determine the temperature and gate voltage dependence of the Coulomb blockade oscillations of the conductance and the effective charge. We find that a small (in comparison with the charging energy) bias voltage leads to significant suppression of the Coulomb blockade oscillations and to appearance of the bias-dependent phase shift.