Current suppression in a double-island single-electron transistor for detection of degenerate charge configurations of a floating double-dot

TL;DR

This study demonstrates how a double-island single-electron transistor can detect degenerate charge states in a floating double-dot by observing current suppression, improving charge state discrimination and noise resilience.

Contribution

It introduces a novel detection method using current suppression in a DISET to identify degenerate charge configurations in a double-dot system.

Findings

Current suppression indicates degenerate charge configurations.

The detection scheme distinguishes degenerate from non-degenerate states.

Reduced susceptibility to charge noise interference.

Abstract

We have investigated a double-island single-electron transistor (DISET) coupled to a floating metal double-dot (DD). Low-temperature transport measurements were used to map out the charge configurations of both the DISET and the DD. A suppression of the current through the DISET was observed whenever the charge configurations of the DISET and the DD were energetically co-degenerate. This effect was used to distinguish between degenerate and non-degenerate charge configurations of the double-dot. We also show that this detection scheme reduces the susceptibility of the DISET to interference from random charge noise.