A theory of spin-polarized electron transport in ferromagnet-semiconductor heterostruc-tures, based on a unified semiclassical description of ballistic and diffusive transport in semiconductors, is outlined. The aim is to provide a framework for studying the interplay of spin relaxation and transport mechanism in spintronic devices. Transport inside the (nondegenerate) semiconductor is describe...

a new derivation of the quantum boltzmann transport equation for the fermion system from the quantum time evolution equation for the wigner distribution function is presented. the method exhibits the origin of the time - irreversibility of the boltzmann equation. in the present work, the spin dependent and indistinguishibility of particles are also considered.

By performing first-principle quantum transport calculations, we studied the electronic and transport properties of zigzag α-graphyne nanoribbons in different magnetic configurations. We designed the device based on zigzag α-graphyne nanoribbon and studied the spin-dependent transport properties, whose current-voltage curves show obvious spin-polarization and conductance plateaus. The interesti...

The interplay between spin and charge transport in electrically and magnetically inhomogeneous semiconductor systems is investigated theoretically. In particular, the theory of spin-polarized bipolar transport in magnetic p-n junctions is formulated, generalizing the classic Shockley model. The theory assumes that in the depletion layer the nonequilibrium chemical potentials of spin-up and spin...

We have performed simulations on electron spin transport in an n-doped silicon bar with spin-dependent conductivity with or without the presence of an external electric field. We further consider three cases like charge neutrality, charge accumulation, and charge depletion at one boundary and found substantial differences in the spin transport behavior. The criteria determining the maximum spin...

We explore electrically injected, spin-polarized transport in a ballistic two-dimensional electron gas. We augment the Büttiker-Landauer picture with a simple, but realistic model for spin-selective contacts to describe multimode reservoir-to-reservoir transport of ballistic spin-1/2 particles. Clear and unambiguous signatures of spin transport are established in this regime, for the simplest m...

We demonstrate spin transport and spin lifetime enhancement in GaAs quantum wells induced by the traveling piezoelectric field of a surface acoustic wave (SAW). Spin transport lengths of about 3 microm corresponding to spin relaxation times during transport over 1 ns are observed, which are considerably longer than the exciton spin diffusion lengths in the absence of a SAW. The slow spin relaxa...

We present a study of spin transport in charge and spin inhomogeneous semiconductor systems. In particular, we investigate the propagation of spin-polarized electrons through a boundary between two semiconductor regions with different doping concentrations. We use a theoretical and numerical method, presented in this paper, based on a self-consistent treatment of a two-component version of the ...

A generalized definition of intrinsic and extrinsic transport coefficients is introduced. We show that transport coefficients from the intrinsic origin are solely determined by local electronic structure, and thus the intrinsic spin Hall effect is not a transport phenomenon. The intrinsic spin Hall current is always accompanied by an equal but opposite intrinsic orbital angular momentum Hall cu...

We present transport measurements of ferromagnetically contacted carbon nanotubes. In both singleand multi-walled nanotube devices, a spin valve effect is observed due to spin-polarized transport. In one single-walled nanotube device, the spin-valve effect is suppressed as the influence of Coulomb charging is observed at around 10 K. To help understand the interplay between the Coulomb charging...