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

Abstract

We observe that an in-plane magnetic field ($B_{||}$) can induce an order of magnitude enhancement in the low temperature ($T$) resistivity ($ρ$) of metallic 2D holes in a narrow (10nm) GaAs quantum well. Moreover, we show the first observation of saturating behavior of $ρ(B_{||})$ at high $B_{||}$ in GaAs system, which suggests our large positive $ρ(B_{||})$ is due to the spin polarization effect alone. We find that this tenfold increase in $ρ(B_{||})$ even persists deeply into the 2D metallic state with the high $B_{||}$ saturating values of $ρ$ 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.