Theory of the anomalous tunnel hall effect at ferromagnet-semiconductor junctions

Abstract

We report on the investigation of carrier tunneling asymmetry at ferromagnet-semiconductor junctions. By an analytical 2×2 spin model, we show that, when Dresselhaus interactions is included in the conduction band of III-V semiconductors (Td or D2d symmetry group), the electrons may undergo a difference of transmission vs. the sign of their incident parallel wavevector normal to the in-plane magnetization. The asymmetry of transmission also exists in the valence band of semiconductors owing to the inner atomic spin-orbit strength and free of asymmetric potentials in bulk or at interfaces. We present advanced multiband 14×14 and 30×30k·p tunneling models together with tunneling transport perturbation calculations based on Green’s function techniques corroborating these results. Those demonstrate that a tunneling spin-current normal to the interface can generate a transverse surface charge current, the so-called Anomalous Tunnel Hall Effect.