Measuring current by counting electrons in a nanowire quantum dot

TL;DR

This paper demonstrates a method to measure current by counting individual electrons tunneling through an InAs nanowire quantum dot, using a nearby quantum point contact as a charge detector, enabling precise electron detection and potential spin manipulation.

Contribution

It introduces a novel electron counting technique for current measurement in nanowire quantum dots, aligning well with direct current measurements while accounting for detector bandwidth.

Findings

Electron counting matches direct current measurements.

Single-electron detection is feasible in nanowire quantum dots.

Potential for spin manipulation and detection at the single-electron level.

Abstract

We measure current by counting single electrons tunneling through an InAs nanowire quantum dot. The charge detector is realized by fabricating a quantum point contact in close vicinity to the nanowire. The results based on electron counting compare well to a direct measurements of the quantum dot current, when taking the finite bandwidth of the detector into account. The ability to detect single electrons also opens up possibilities for manipulating and detecting individual spins in nanowire quantum dots.