Dispersive readout of a silicon quantum dot with an accumulation-mode gate sensor

TL;DR

This paper demonstrates dispersive readout of a silicon quantum dot using an accumulation-mode gate sensor, highlighting how bias voltage influences the sensor's response and discussing the underlying capacitive effects.

Contribution

It introduces a gate-based dispersive readout method for silicon quantum dots and analyzes the impact of bias voltage on the sensor's response, advancing scalable qubit readout techniques.

Findings

Gate detector response is significantly affected by bias voltage.

Bias exceeding the electron accumulation threshold alters dispersive response.

Capacitive contributions explain the observed response variations.

Abstract

Sensitive charge detection has enabled qubit readout in solid-state systems. Recently, an alternative to the well-established charge detection via on-chip electrometers has emerged, based on in situ gate detectors and radio-frequency dispersive readout techniques. This approach promises to facilitate scalability by removing the need for additional device components devoted to sensing. Here, we perform gate-based dispersive readout of an accumulation-mode silicon quantum dot. We observe that the response of an accumulation-mode gate detector is significantly affected by its bias voltage, particularly if this exceeds the threshold for electron accumulation. We discuss and explain these results in light of the competing capacitive contributions to the dispersive response.