Storage capabilities of a 4-junction single electron trap with an on-chip resistor

TL;DR

This paper demonstrates a four-junction single electron trap with an on-chip resistor that effectively suppresses cotunneling, enabling long-term charge storage at cryogenic temperatures.

Contribution

It introduces a novel four-junction electron trap integrated with a resistor to enhance charge retention and reduce cotunneling effects.

Findings

Charge states are stable for over 2 hours at 70 mK.

The on-chip resistor effectively suppresses cotunneling.

Bi-stable charge states are reliably achieved.

Abstract

We report on the operation of a single electron trap comprising a chain of four Al/AlOx/Al tunnel junctions attached, at one side, to a memory island and, at the other side, to a miniature on-chip Cr resistor R=50 kOhm which served to suppress cotunneling. At appropriate voltage bias the bi-stable states of the trap, with the charges differing by the elementary charge e, were realized. At low temperature, spontaneous switching between these states was found to be infrequent. For instance, at T=70 mK the system was capable of holding an electron for more than 2 hours, this time being limited by the time of the measurement.