Non-adiabatic pumping of single electrons affected by magnetic fields

TL;DR

This paper investigates how a perpendicular magnetic field influences non-adiabatic single-electron pumping in a quantum dot system, revealing distinct behaviors for even and odd electron numbers through experimental and theoretical analysis.

Contribution

It extends existing theory to multiple electrons, demonstrating magnetic field effects on quantized charge pumping and highlighting differences between even and odd electron pumping regimes.

Findings

Quantized current plateaus observed under GHz oscillating voltages.

Distinct behaviors for even versus odd electron pumping in magnetic fields.

Theoretical extension explaining the influence of magnetic fields on multi-electron pumping.

Abstract

Non-adiabatic pumping of discrete charges, realized by a dynamical quantum dot in an AlGaAs/GaAs heterostructure, is studied under influence of a perpendicular magnetic field. Application of an oscillating voltage in the GHz-range to one of two top gates, crossing a narrow wire and confining a quantum dot, leads to quantized pumped current plateaus in the gate characteristics. The regime of pumping one single electron is traced back to the diverse tunneling processes into and out-of the dot. Extending the theory to multiple electrons allows to investigate conveniently the pumping characteristics in an applied magnetic field. In this way, a qualitatively different behavior between pumping even or odd numbers of electrons is extracted.