Large bias-tunable magnetoresistance from spin-dependent interlayer hybridization in van der Waals antiferromagnet CrSBr-based heterostructures

We explore the large magnetoresistance (MR) in \ce{hBN}/few-layer-graphene/\ce{CrSBr}/few-layer-graphene heterostructures and reveal the mechanism behind its non-monotonic bias dependence. Using bias voltage and temperature as independent tuning knobs, we achieve MR up to \SI{350}{\percent} at \SI{20}{K}, characterized by symmetric M-shaped maxima around $\pm 0.5\mathrm{V}$. Continuous tuning of the magnetization angle $\theta$ via a hard-axis magnetic field shows that the barrier band-edge offset varies linearly with $\cos (\theta \mathrm{/}2)$, a first-order signature of spin-dependent interlayer hybridization. This linear relationship rules out the Julli`ere model and a spin-filter projection. We conclude that the magnetic-configuration-dependent band edge, rather than electrode spin polarization, dictates the large magnetoresistance in \ce{CrSBr} junctions.