Spin-Dependent Tunneling of Single Electrons into an Empty Quantum Dot

TL;DR

This paper investigates how spin-dependent tunneling rates of single electrons into a quantum dot vary with magnetic field and orbital configuration, revealing control over spin state tunneling through gate voltages.

Contribution

It demonstrates the ability to manipulate spin-dependent tunneling rates by adjusting gate voltages, providing insights into spin control in quantum dots.

Findings

Tunneling into excited spin states decreases with magnetic field.

Adjusting gate voltages can restore tunneling into excited states.

Maximum tunneling ratio occurs when the quantum dot is symmetric.

Abstract

Using real-time charge sensing and gate pulsing techniques we measure the ratio of the rates for tunneling into the excited and ground spin states of a single-electron AlGaAs/GaAs quantum dot in a parallel magnetic field. We find that the ratio decreases with increasing magnetic field until tunneling into the excited spin state is completely suppressed. However, we find that by adjusting the voltages on the surface gates to change the orbital configuration of the dot we can restore tunneling into the excited spin state and that the ratio reaches a maximum when the dot is symmetric.