Preparation and Readout of Multielectron High-Spin States in a Gate-Defined GaAs/AlGaAs Quantum Dot

TL;DR

This paper demonstrates a method to prepare and read out high-spin states in GaAs/AlGaAs quantum dots, revealing faster relaxation rates for high-spin states and providing a new tool for quantum spin research.

Contribution

The paper introduces a novel readout scheme for multielectron high-spin states in quantum dots, simplifying detection and enabling new studies of high-spin dynamics.

Findings

High-spin states relax faster than low-spin states.

The readout scheme maps multielectron states to two-electron states.

Numerical calculations agree with experimental relaxation rates.

Abstract

We report the preparation and readout of multielectron high-spin states, a three-electron quartet, and a four-electron quintet, in a gate-defined GaAs/AlGaAs single quantum dot using spin filtering by quantum Hall edge states coupled to the dot. The readout scheme consists of mapping from multielectron to two-electron spin states and a subsequent two-electron spin readout, thus obviating the need to resolve dense multielectron energy levels. Using this technique, we measure the relaxations of the high-spin states and find them to be an order of magnitude faster than those of low-spin states. Numerical calculations of spin relaxation rates using the exact diagonalization method agree with the experiment. The technique developed here offers a new tool for the study and application of high-spin states in quantum dots.