Spin Accumulation and Spin Relaxation in a Large Open Quantum Dot

TL;DR

This paper demonstrates electronic control and measurement of spin imbalance in open quantum dots, enabling the extraction of spin relaxation times and contact polarization, advancing spintronics research.

Contribution

It introduces a method to control and measure spin accumulation in quantum dots using quantum point contacts, providing new insights into spin relaxation and polarization.

Findings

Spin relaxation time ~ 300 ps

Contact polarization P ~ 0.8

Non-local spin-valve circuit implementation

Abstract

We report electronic control and measurement of an imbalance between spin-up and spin-down electrons in micron-scale open quantum dots. Spin injection and detection was achieved with quantum point contacts tuned to have spin-selective transport, with four contacts per dot for realizing a non-local spin-valve circuit. This provides an interesting system for studies of spintronic effects since the contacts to reservoirs can be controlled and characterized with high accuracy. We show how this can be used to extract in a single measurement the relaxation time for electron spins inside the dot ~ 300 ps and the degree of spin polarization of the contacts P ~ 0.8.