Charge sensing in carbon nanotube quantum dots on microsecond timescales

TL;DR

This paper demonstrates rapid charge sensing and transport measurements in carbon nanotube quantum dots using rf-SETs and reflectometry, revealing detailed charge stability and Coulomb blockade features.

Contribution

It introduces a method for simultaneous, high-speed charge sensing and transport measurement in nanotube quantum dots, enabling detailed analysis of charge states.

Findings

Charge sensing on microsecond timescales achieved.

Extended Coulomb diamonds observed in high-bias regime.

Even-odd filling effects detected in charge data.

Abstract

We report fast, simultaneous charge sensing and transport measurements of gate-defined carbon nanotube quantum dots. Aluminum radio frequency single electron transistors (rf-SETs) capacitively coupled to the nanotube dot provide single-electron charge sensing on microsecond timescales. Simultaneously, rf reflectometry allows fast measurement of transport through the nanotube dot. Charge stability diagrams for the nanotube dot in the Coulomb blockade regime show extended Coulomb diamonds into the high-bias regime, as well as even-odd filling effects, revealed in charge sensing data.