Counting statistics of cotunneling electrons

TL;DR

This paper introduces a perturbative method to calculate the full counting statistics of electron transport in nanoscale devices, accounting for both sequential tunneling and cotunneling effects, without additional approximations.

Contribution

It presents a novel approach using a nonMarkovian master equation derived from a perturbative expansion of the von Neumann equation for accurate counting statistics.

Findings

Cotunneling significantly affects noise and skewness in quantum dot transport.

The method accurately captures nonMarkovian effects in electron counting statistics.

Comparison of approximation schemes reveals their limitations in modeling cotunneling.

Abstract

We describe a method for calculating the counting statistics of electronic transport through nanoscale devices with both sequential and cotunneling contributions. The method is based upon a perturbative expansion of the von Neumann equation in Liouvillian space, with current cumulants calculated from the resulting nonMarkovian master equation without further approximation. As application, we consider transport through a single quantum dot and discuss the effects of cotunneling on noise and skewness, as well as the properties of various approximation schemes.