We report on theoretical investigations of carrier scattering 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 T d symmetry group semiconductors, the electrons may undergo a difference of transmission vs. the sign of their incident parallel wavevector normal to the in-plane magnetization. This asymmetry is universally scaled by a unique function independent of the spin-orbit strength. This particular feature is reproduced by a multiband k · p tunneling transport model. Astonishingly, the asymmetry of transmission persists in the valence band of semiconductors owing to the inner atomic spin-orbit strength and free of asymmetric potentials . We present multiband 14 × 14 and 30 × 30 k · p tunneling models together with tunneling transport perturbation calculations corroborating these results. Those demonstrate that a tunnel spin-current normal to the interface can generate a surface transverse charge current, the so-called Anomalous Tunnel Hall Effect. PACS numbers: 72.25.Mk, 75.70.Tj, 75.76.+j
I -INTRODUCTIONSpinorbitronics is a science that uses the spin degree of freedom together with the spin-orbit interactions (SOI) to generate spin-currents without the need of a ferromagnetic material. Those spin-currents become essential in view to control the magnetization state of a nanomagnet, via the spin-Hall effect of heavy material either semiconductor [1][2][3][4][5] or metals [6,[12][13][14][15]. The interplay between particle spin and orbital motion is currently at the basis of a new family of effects like the Anomalous Tunnel Hall effect described by the generation of a charge current transverse to a tunneling spin-current [7][8][9][10] or the spin-galvanic effects [11]. SOI at an interface with broken inversion symmetry may lead to the observation of Rashba-split states [16,17] which may be used to convert a flow of spin-current into a transverse charge current by inverse Edelstein effect (IEE) [18,19]. Recent magnetoresistance (MR) measurements with an unidirectional character (UMR) have been evidenced in metallic [20] and semiconductor bilayers [21] as well as with topological insulator (TI) [22]. It was ascribed to the asymmetric scattering of electrons by magnons absorption-emission processes at ferromagnet-TI interfaces. It clearly reveals a novel symmetry in the field of MR explained by a certain carrier scattering asymmetry incorporated in the Boltzmann transport equation developed at the second order. An anisotropy of electronic diffusion on the Fermi surface along the current direction leads to a supplementary non-linear contribution of M R proportional to the current.In this article, as an extension to our previous work [9], we study unconventional quantum effects resulting in a giant transport asymmetry of carriers in semiconductor heterostructures, interfaces, tunnel barriers or quantum wells. Those are composed of ferromagnets and spin-orbit split electrodes made of semicond...
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