Giant current fluctuations in an overheated single electron transistor

TL;DR

This paper investigates giant current fluctuations in an overheated single-electron transistor caused by the exponential sensitivity of current to temperature fluctuations, revealing a regime with extremely large and non-Gaussian current variability.

Contribution

It provides a detailed analysis of current and temperature fluctuations in overheated SETs, including the distribution beyond Gaussian approximation, and identifies a regime with colossal current fluctuations.

Findings

Current fluctuations can become gigantic in small SETs.

The current's expectation, optimal, and standard deviation differ greatly in this regime.

The exponential dependence of current on temperature causes extreme sensitivity and large fluctuations.

Abstract

Interplay of cotunneling and single-electron tunneling in a thermally isolated single-electron transistor (SET) leads to peculiar overheating effects. In particular, there is an interesting crossover interval where the competition between cotunneling and single-electron tunneling changes to the dominance of the latter. In this interval, the current exhibits anomalous sensitivity to the effective electron temperature of the transistor island and its fluctuations. We present a detailed study of the current and temperature fluctuations at this interesting point. The methods implemented allow for a complete characterization of the distribution of the fluctuating quantities, well beyond the Gaussian approximation. We reveal and explore the parameter range where, for sufficiently small transistor islands, the current fluctuations become gigantic. In this regime, the optimal value of the current, its expectation value, and its standard deviation differ from each other by parametrically large factors. This situation is unique for transport in nanostructures and for electron transport in general. The origin of this spectacular effect is the exponential sensitivity of the current to the fluctuating effective temperature.