Spin polarization induced tenfold magneto-resistivity of highly metallic 2D holes in a narrow GaAs quantum well

TL;DR

This study demonstrates that an in-plane magnetic field can induce a tenfold increase in resistivity of highly metallic 2D holes in GaAs, revealing spin polarization effects that significantly impact transport properties.

Contribution

First observation of saturating magneto-resistivity in GaAs 2D holes due to spin polarization, with resistivity enhancement persisting into the metallic state at high magnetic fields.

Findings

Resistivity increases tenfold with in-plane magnetic field.

Resistivity saturates at high magnetic fields, indicating spin polarization.

High conductivity 2D holes are strongly affected by magnetic fields.

Abstract

We observe that an in-plane magnetic field ($B_{||}$) can induce an order of magnitude enhancement in the low temperature ($T$) resistivity ($\rho$) of metallic 2D holes in a narrow (10nm) GaAs quantum well. Moreover, we show the first observation of saturating behavior of $\rho(B_{||})$ at high $B_{||}$ in GaAs system, which suggests our large positive $\rho(B_{||})$ is due to the spin polarization effect alone. We find that this tenfold increase in $\rho(B_{||})$ even persists deeply into the 2D metallic state with the high $B_{||}$ saturating values of $\rho$ lower than 0.1$\times$h/e$^2$. The dramatic effect of $B_{||}$ we observe on the highly conductive 2D holes (with $B$=0 conductivity as high as 75e$^2$/h) sets strong constraint on models for the spin dependent transport in dilute metallic 2D systems.