Proceedings Article | 10 September 2019
KEYWORDS: Heterojunctions, Group III-V semiconductors, Magnetic semiconductors, Semiconductors, Interfaces, Ferromagnetics, System on a chip, Particles, Quantum wells, Reflection
Spinorbitronics in III-V semiconductors, e.g. involving the GaMnAs ferromagnetic semiconductors, uses the properties of spin-orbit coupling (SOC) to generate currents of angular momentum [1-2]. Thoses are now essential to control the magnetization state of a magnet [3], or moving a domain wall [4] via the generalized spin-Hall effect of III-V possibly involving Rashba and Dresselhaus terms [4]. The interplay between particle spin and orbital motion is also at the basis of new families of effects played e. g. by the Anomalous Tunnel Hall effect described by the appearance of a lateral charge current transverse to a tunneling spin-current [5–7] ; or the spin-galvanic effects [8]. The ensemble of those complex phenomena requires a clear description of the spin-currents anatomy with advance calculation tools.
In this work, as an extension to previous contributions [5], we study unconventional quantum effects resulting in a giant transport asymmetry of carriers and spin-to-charge conversion in semiconductor interfaces, tunnel barriers or quantum wells. Those are composed of ferromagnets and strong spin-orbit materials, e. g. III-V compounds with magnetizations of opposite direction (AP) or in the geometry of spin-injection devices. The symmetry of the structure allows a difference of transmission upon respective positive or negative incidence vs. the reflection plane defined by the magnetization and the surface normal. We will restrict ourself to the effect of bulk Dresselhaus terms by using the simplest form of the quantum boundary conditions. We will first detail the robustness of our advanced 30-band and 40 band tunneling codes free of spurious states effects and involving the higher electronic bands involving the relevant spin-orbit contributions. We will demonstrate that refined boundary conditions involving surface potentials, like Rashba terms, arising from the symmetry breaking at interfaces may lead to equivalent effects by their own. In a second part, we emphasize on the perturbation calculation techniques needed to understand this phenomena and to the case of the core SOI in the valence band (VB).
References: [1] Tomasz Dietl and Hideo Ohno, Rev. Mod. Phys. 86, 187 (2014).
[2] T. Jungwirth et al., Rev. Mod. Phys. 86, 855 (2014).
[3] M. Elsen et al., Phys. Rev. B 73, 035303
[4] L. Thevenard et al., Phys. Rev. B 95, 054422 (2017).
[5] T. Huong Dang, H. Jaffrès, T. L. Hoai Nguyen, and H.-J. Drouhin, Phys. Rev. B 92, 060403(R) (2015).
[6] A. Matos-Abiague and J. Fabian, Phys. Rev. Lett. 115, 056602 (2015).
[7] M. Jamet, A. Barski, T. Devillers, V. Poydenot et al., Nat. Mat. 5, 653-659 (2006).
[10] S. D. Ganichev et al., Spinpolarization by current, ""Handbook of spin-transport & magnetism"", (Chapman and Hall), 2016.
