Spin-depedent transmission of holes through periodically modulated   diluted magnetic semiconductor waveguides
  We study spin transport of holes through stubless or stubbed waveguides modulated periodically by diluted magnetic semiconductor (DMS) sections of width b1 . Injected holes of up (down) spin feel a periodically modulated barrier (well) potential in the DMS sections and have different transmission (T) coefficients. T oscillates with b1 for spin-down and decreases fast for spin-up holes while the relative polarization Pr depends nearly periodically on the stub height. Using asymmetric stubs leads to a nearly square-wave pattern in T and to wide plateaus in Pr . T oscillates with the length between the DMS sections. With two DMS sections per unit, T shows periodically wide gaps for spin-down holes when a DMS width is varied. The results can be used to create efficient spin filters. 
X. F. Wang and P. Vasilopoulos