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The effects of electro-magnetic confining potentials and the s–d exchange interaction between substituted Mn ions and carriers on the spin polarization of carriers in an diluted magnetic semiconductor quantum dot are investigated within the framework of the effective-mass theory. The energy eigenvalues and wavefunctions of a single electron in the presence of an external magnetic field are studied by solving the one particle Schrödinger equation including the conventional Zeeman effect, the s–d exchange interaction and the electric confining potential which describes the dot. The eigenenergy structure for low lying states is strongly dependant on the relative sizes of the s–d exchange interactions and the conventional Zeeman energy splitting. When the spin splitting exceeds the cyclotron energy splitting, the Landau level overlappings occur so that the spin polarization of carriers is induced in low lying energy states. This spin polarization of carriers in the diluted magnetic semiconductor quantum dot can be controlled by changing the electro-magnetic confining potentials. [ABSTRACT FROM AUTHOR]

The current induced local spin polarization due to weak Rashba spin-orbit coupling in narrow strip is studied. In the presence of longitudinal charge current, local spin polarizations appear in the sample. The spin polarization perpendicular to the plane has opposite sign near the two edges. The in-plane spin polarization in the direction perpendicular to the sample edges also appears, but does not change sign across the sample. From our scaling analysis based on increasing the strip width, the out-of-plane spin polarization is important mainly in a system of mesoscopic size, and thus appears not to be associated with the spin-Hall effect in bulk samples. [ABSTRACT FROM AUTHOR]

We theoretically investigate the spin-dependent transport properties of electrons in realistic magnetic-electric barrier nanostructures, which are produced by the deposition, on top of a heterostructure, of a metallic ferromagnetic stripe with an applied voltage. The degree of the electron-spin polarization is found to be closely associated with this voltage, although the use of applied voltage itself induces no spin polarization effect. As a positive voltage is applied to the stripe the electron-spin polarization shifts towards the low-energy region and increases; it shifts towards the high-energy direction and reduces for a negative applied voltage. These results shown in this work imply that the degree of electron-spin polarization can be tuned by means of an applied voltage on the stripes of system, which may result in a practical voltage-controlled spin filter. [ABSTRACT FROM AUTHOR]

We study the magnetization and the magnetic phases of II-VI-based n-doped nonmagnetic- semiconductor (NMS) / narrow to wide dilute-magnetic-semiconductor (DMS) / n-doped NMS quantum wells under in-plane magnetic field. The parallel magnetic field is used as a tool, in order to achieve non-step-like density of states in these -appropriate for conduction-band spintronics- structures. [ABSTRACT FROM AUTHOR]