We propose an electronic spin-filter device that uses a nonmagnetic triple barrier resonant tunneling diode (TB-RTD). This device combines the spin-split resonant tunneling levels induced by the Rashba spin-orbit interaction and the spin blockade phenomena between two regions separated by the middle barrier in the TB-RTD. Detailed calculations using the InAlAs/InGaAs material system reveal that a splitting of a peak should be observed in the $I-V$ curve of this device as a result of the spin-filtering effect. The filtering efficiency exceeds $99.9\%$ at the peak positions in the $I-V$ curve.

• Received 1 October 2001

DOI:https://doi.org/10.1103/PhysRevLett.88.126601