Spin polarization and transition from metallic to insulating behavior in 2D systems

TL;DR

This study quantitatively measures spin polarization in 2D GaAs and AlAs systems, revealing a transition from metallic to insulating behavior before full spin polarization, linking magnetoresistance to spin states.

Contribution

It provides new experimental insights into the relationship between spin polarization and electronic phase transitions in various 2D semiconductor systems.

Findings

Spin polarization measured as a function of in-plane magnetic field.

Metallic to insulating transition occurs before full spin polarization.

Magnetoresistance behavior is closely related to spin polarization.

Abstract

We have made quantitative measurements of the spin polarization of two-dimensional (2D) GaAs (100) electrons and GaAs (311)A holes, as a function of an in-plane magnetic field. The functional form of the in-plane magnetoresistance is shown to be intimately related to the spin polarization. Moreover, for three different 2D systems, namely GaAs (100) electrons, GaAs (311)A holes, and AlAs (411)B electrons, the temperature dependence of the in-plane magnetoresistance reveals that their behavior turns from metallic to insulating before they are fully spin polarized.