Spin filtering devices based on ferromagnetic stripe modulated double quantum-dot structures

We report on a theoretical study of spin-dependent electron transport in double quantum dot structures, made from a two-dimensional electron gas, with a local magnetic field modulation. Spin-dependent conductance and probability density of electrons in the structures are calculated and the underlying physics of the results is discussed. We include in the study not only the magnetic field component perpendicular to the two-dimensional electron gas plane, but also a consideration of the in-plane component of the magnetic field. It is shown that giant spin polarization (similar to 100%) of the conductance, with tunable spin polarity, can be achieved with the double-dot structures. It is also shown that the structures can be used as efficient spin filtering devices at temperatures well above that defined by the spin splitting energy.