Theory of Spin Hall Effects in Semiconductors
arXiv:cond-mat/0603306
Abstract
Spin Hall effects are a collection of phenomena, resulting from spin-orbit coupling, in which an electrical current flowing through a sample can lead to spin transport in a perpendicular direction and spin accumulation at lateral boundaries. These effects, which do not require an applied magnetic field, can originate in a variety of intrinsic and extrinsic spin-orbit coupling mechanisms and depend on geometry, dimension, impurity scattering, and carrier density of the system--making the analysis of these effects a diverse field of research. In this article, we give an overview of the theoretical background of the spin Hall effects and summarize some of the most important results. First, we explain effective spin-orbit Hamiltonians, how they arise from band structure, and how they can be understood from symmetry considerations; including intrinsic coupling due to bulk inversion or structure asymmetry or due to strain, and extrinsic coupling due to impurities. This leads to different mechanisms of spin transport: spin precession, skew scattering, and side jump. Then we present the kinetic (Boltzmann) equations, which describe the spin-dependent distribution function of charge carriers, and the diffusion equation for spin polarization density. Next, we define the notion of spin currents and discuss their relation to spin polarization. Finally, we explain the electrically induced spin effects; namely, spin polarization and currents in bulk and near boundaries (the focus of most current theoretical research efforts), and spin injection, as well as effects in mesoscopic systems and in edge states.
Contribution to Handbook of Magnetism and Advanced Magnetic Materials, Vol. 5, Wiley. 37 pages, 5 figures; slightly extended text and updated references; final version
References in corpus (12)
- Dissipationless Quantum Spin Current at Room Temperature
- Spin current and polarization in impure 2D electron systems with spin-orbit coupling
- Current induced electron spin polarization in strained semiconductors
- Theory of Spin Hall conductivity in n-doped GaAs
- Spin-Hall transport of heavy holes in III-V semiconductor quantum wells
- Intrinsic Spin Hall Edges
- Spin Hall Current Driven by Quantum Interferences in Mesoscopic Rashba Rings
- Small-angle impurity scattering and the spin Hall conductivity in 2D systems
- Out-of-plane spin polarization from in-plane electric and magnetic fields
- Spin susceptibilities, spin densities and their connection to spin-currents
- Polarized Electric Current in Semiclassical Transport with Spin-Orbit Interaction
- Can an electric current orient spins in quantum wells?