Numerical Simulation of Quantized Current Generated by a Quantum Dot Pump

TL;DR

This paper presents a numerical simulation method for quantized current in quantum dot pumps, demonstrating agreement with experimental data and analyzing factors affecting current accuracy for quantum standards.

Contribution

The paper introduces a numerical approach dividing time-varying potentials into static segments to simulate quantum dot pump currents, providing insights into back-tunneling effects and optimization strategies.

Findings

Simulation results align qualitatively with experimental data.

Back-tunneling significantly impacts current plateau accuracy.

Increasing entrance gate width improves pump current precision.

Abstract

The quantized current generated by a quantum dot pump is calculated numerically. The numerical simulation is done by dividing the time varying potential into many static potentials with a short time interval and calculating the electron capture and pumping rate with the time independent Schrodinger equation. The simulation results show good agreement with reported experimental results qualitatively. The calculated 2D pump current map and the plateau width dependence on the modulation gate voltage show good agreement with the experimental results. From the simulation results, it is explained how the back-tunneling process affects the accuracy of the current plateaus quantitatively. Also, the energy distribution of the pumped electron is calculated, which can be measured experimentally. Finally, it is found that the pump current accuracy can be enhanced by increasing the entrance gate width, which is important to realize the quantum current standard.