Theory of the Bloch Oscillating Transistor

TL;DR

This paper develops a theoretical model of the Bloch oscillating transistor as a two-level system, predicting its electrical characteristics, noise behavior, and stability regimes, validated by simulations.

Contribution

It introduces a novel two-level system model for the BOT, providing analytical predictions for its operation and noise characteristics, advancing understanding of its dynamics.

Findings

Predicted current-voltage characteristics and small-signal response.

Identified switching noise as the main source of fluctuations.

Analyzed transition to hysteretic regime and noise temperature.

Abstract

The Bloch oscillating transistor (BOT) is a device, where single electron current through a normal tunnel junction can be used to enhance Cooper pair current in a mesoscopic Josephson junction leading to signal amplification. In this paper we develop a theory, where the BOT dynamics is described as a two-level system. The theory is used to predict current-voltage characteristics and small-signal response. Transition from stable operation into hysteretic regime is studied. By identifying the two-level switching noise as the main source of fluctuations, the expressions for equivalent noise sources and the noise temperature are derived. The validity of the model is tested by comparing the results with simulations.