# Quantum Hall Spin Diode

## TL;DR

This paper demonstrates that high-quality double-layer 2D electron systems under strong magnetic fields can act as nearly ideal spin diodes, revealing full spin polarization at certain Landau level filling factors and weak Landau level mixing.

## Contribution

It introduces a novel high-magnetic-field double-layer system functioning as a spin diode, providing insights into spin polarization and Landau level mixing at specific filling factors.

## Key findings

- The tunnel junction acts as a nearly ideal spin diode at low temperatures.
- Electrons at filling factors 5/2 and 7/2 are nearly fully spin polarized.
- Landau level mixing at these filling factors is weak in the studied samples.

## Abstract

Double layer two-dimensional electron systems at high perpendicular magnetic field are used to realize magnetic tunnel junctions in which the electrons at the Fermi level in the two layers have either parallel or anti-parallel spin magnetizations. In the anti-parallel case the tunnel junction, at low temperatures, behaves as a nearly ideal spin diode. At elevated temperatures the diode character degrades as long-wavelength spin waves are thermally excited. These tunnel junctions provide a demonstration that the spin polarization of the electrons in the $N=1$ Landau level at filling factors $\nu = 5/2$ and 7/2 is essentially complete, and, with the aid of an in-plane magnetic field component, that Landau level mixing at these filling factors is weak in the samples studied.