Spin Transition in the Half-Filled Landau Level

TL;DR

This study investigates the spin polarization transition in a two-dimensional electron system at half filling of the Landau level, revealing a sharp change in nuclear relaxation times and a maximum in RDNMR signal near the critical density.

Contribution

It provides experimental evidence of the spin transition using resistively-detected NMR, highlighting the behavior of nuclear relaxation times at the transition point.

Findings

Nuclear spin-lattice relaxation time is density independent in the partial polarization phase.

Relaxation time sharply increases at the transition to full polarization.

RDNMR signal shows a strong maximum near the critical density at low temperatures.

Abstract

The transition from partial to complete spin polarization of two-dimensional electrons at half filling of the lowest Landau level has been studied using resistively-detected nuclear magnetic resonance (RDNMR). The nuclear spin-lattice relaxation time is observed to be density independent in the partially polarized phase but to increase sharply at the transition to full polarization. At low temperatures the RDNMR signal exhibits a strong maximum near the critical density.