Knight shift detection using gate-induced decoupling of the hyperfine interaction in quantum Hall edge channels

TL;DR

This paper introduces a highly sensitive method to detect the Knight shift in nanometer-scale semiconductor regions using gate-controlled decoupling of hyperfine interactions in quantum Hall edge channels, enhancing NMR measurement precision.

Contribution

The study develops a novel resistively detected NMR technique utilizing gate-induced hyperfine decoupling to measure Knight shifts in quantum Hall edge channels.

Findings

Successfully measured Knight shifts in quantum Hall edge channels.

Demonstrated high sensitivity compared to conventional NMR.

Enabled detection of nuclear spin polarization in nanoscale regions.

Abstract

A method for the observation of the Knight shift in nanometer-scale region in semiconductors is developed using resistively detected nuclear magnetic resonance (RDNMR) technique in quantum Hall edge channels. Using a gate-induced decoupling of the hyperfine interaction between electron and nuclear spins, we obtain the RDNMR spectra with or without the electron-nuclear spin coupling. By a comparison of these two spectra, the values of the Knight shift can be given for the nuclear spins polarized dynamically in the region between the relevant edge channels in a single two-dimensional electron system, indicating that this method has a very high sensitivity compared to a conventional NMR technique.