An accurate single-electron pump based on a highly tunable silicon quantum dot

TL;DR

This paper presents a silicon-based quantum dot single-electron pump with tunable tunnel barriers that achieves high accuracy and robustness in quantized current generation, advancing quantum current standards.

Contribution

It introduces a highly tunable silicon quantum dot pump with improved accuracy and stability through electrostatic control and gate voltage optimization.

Findings

Output current exceeds 80 pA.

Relative uncertainty below 50 ppm.

Enhanced robustness and suppression of non-adiabatic transitions.

Abstract

Nanoscale single-electron pumps can be used to generate accurate currents, and can potentially serve to realize a new standard of electrical current based on elementary charge. Here, we use a silicon-based quantum dot with tunable tunnel barriers as an accurate source of quantized current. The charge transfer accuracy of our pump can be dramatically enhanced by controlling the electrostatic confinement of the dot using purposely engineered gate electrodes. Improvements in the operational robustness, as well as suppression of non-adiabatic transitions that reduce pumping accuracy, are achieved via small adjustments of the gate voltages. We can produce an output current in excess of 80 pA with experimentally determined relative uncertainty below 50 parts per million.