NMR Evidence for Spin Canting in a Bilayer nu = 2 Quantum Hall System

TL;DR

This study uses NMR techniques to reveal the spin configuration in a bilayer quantum Hall system at nu=2, providing direct evidence for spin canting and showing how spin polarization varies with density imbalance.

Contribution

It offers the first direct NMR evidence of spin canting in a bilayer quantum Hall system at nu=2, elucidating the spin structure and its dependence on density imbalance.

Findings

Continuous variation of out-of-plane spin polarization with density imbalance

Development of an in-plane spin component during the experiment

Direct evidence supporting the spin canting hypothesis

Abstract

We investigate the electron spin states in the bilayer quantum Hall system at total Landau level filling factor nu =2 exploiting current-pumped and resistively detected NMR. The measured Knight shift, KS, of 75As nuclei reveals continuous variation of the out-of-plane electronic spin polarization between nearly full and zero as a function of density imbalance. Nuclear spin relaxation measurements indicate a concurrent development of an in-plane spin component. These results provide direct information on the spin configuration in this system and comprise strong evidence for the spin canting suggested by previous experiments.