Landau Level Single-Electron Pumping

TL;DR

This study investigates how strong magnetic fields influence single-electron pumping in a quantum Hall device, revealing oscillations linked to Landau levels and developing a new theory to extract key physical parameters.

Contribution

It provides the first detailed analysis of magnetic field effects on single-electron pumps and introduces a theoretical model to determine physical parameters from experimental data.

Findings

Pumping exhibits oscillations similar to Shubnikov-de Haas effects.

Pumping process depends on the density of states of the 2D electron gas.

New theoretical framework enables extraction of electron capture energy, Landau level broadening, and quantum lifetime.

Abstract

We present the first detailed study of the effect of a strong magnetic field on single-electron pumping in a device utilising a finger-gate split-gate configuration. In the quantum Hall regime, we demonstrate electron pumping from Landau levels in the leads, where the measurements exhibit pronounced oscillations in the lengths of the pumping plateaus with the magnetic field, reminiscent of Shubnikov-de Haas oscillations. This similarity indicates that the pumping process is dependent on the density of states of the 2D electron gas over a narrow energy window. Based on these observations, we develop a new theoretical description of the operation of single-electron pumps which for the first time allows for the determination of the physical parameters of the experiment; such as the capture energy of the electrons, the broadening of the quantised Landau levels in the leads, and the quantum lifetime of the electrons.