Dynamic Nuclear Polarization and Nuclear Magnetic Resonance in the Simplest Pseudospin Quantum Hall Ferromagnet

TL;DR

This paper demonstrates dynamic nuclear polarization in a pseudospin quantum Hall ferromagnet of InSb, revealing domain structure effects and nuclear magnetic resonance detection of 115In with quadrupole splittings.

Contribution

It introduces DNP in a simple pseudospin QHF using tilted magnetic fields and observes NMR signals with quadrupole splittings, highlighting domain structures' role.

Findings

DNP causes measurable resistance changes in the QHF.

NMR of 115In with quadrupole splittings detected.

Nuclear spin relaxation time T1 is about 120 seconds and temperature independent.

Abstract

We present dynamic nuclear polarization (DNP) in the simplest pseudospin quantum Hall ferromagnet (QHF) of an InSb two-dimensional electron gas with a large g factor using tilted magnetic fields. The DNP-induced amplitude change of a resistance spike of the QHF at large current enables observation of the resistively detected nuclear magnetic resonance of the high nuclear spin isotope 115In with nine quadrupole splittings. Our results demonstrate the importance of domain structures in the DNP process. The nuclear spin relaxation time T1 in this QHF was relatively short (~ 120 s), and almost temperature independent.