Spin currents modulated by magnetic barriers in semiconductor nanowires

Abstract

We present the properties of ballistic spin transport through magnetic barrier structures in semiconductor nanowires. Landauer's approach is adopted for the calculation of spin transport properties for various host material nanowires which are remarkably different from each other in the effective g-factor, g*. The spin polarization effect on the conductance of a nanowire is more efficient than that of a purely two-dimensional electron gas. Especially, when the bias increases the conductance of a nanowire with small g* is quantized as a step function and its spin dependence disappears. However, these behaviours are broken for a host material with large g* and the spin-dependent splitting appears in this case. We achieve the enhancement of the spin polarization effect on currents by increasing the number of magnetic barriers and we can finally obtain the perfect spin-polarized effect on the conductance.