Thermal properties of charge noise sources

TL;DR

This paper investigates how charge noise in Single Electron Transistors (SETs) depends on temperature and bias, revealing that noise increases linearly with temperature above a threshold and is influenced by self-heating and electron tunneling.

Contribution

It demonstrates the thermal contact between two-level fluctuators and electrons in SETs, and explains the temperature dependence of charge noise with self-heating effects.

Findings

Charge noise increases linearly with temperature above a threshold.

Self-heating causes saturation of charge noise at low temperatures.

Charge noise is linked to electron tunneling between SET and potential wells.

Abstract

Measurements of the temperature and bias dependence of Single Electron Transistors (SETs) in a dilution refrigerator show that charge noise increases linearly with refrigerator temperature above a voltage-dependent threshold temperature, and that its low temperature saturation is due to SET self-heating. We show further that the two-level fluctuators responsible for charge noise are in strong thermal contact with the electrons in the SET, which can be at a much higher temperature than the substrate. We suggest that the noise is caused by electrons tunneling between the SET metal and nearby potential wells.