Robustness of spin filtering against current leakage in a Rashba-Dresselhaus-Aharonov-Bohm interferometer

Abstract

In an earlier paper [Phys. Rev. B 84, 035323 (2011)], we proposed a spin filter which was based on a diamond-like interferometer, subject to both an Aharonov-Bohm flux and (Rashba and Dresselhaus) spin-orbit interactions. Here we show that the full polarization of the outgoing electron spins remains the same even when one allows leakage of electrons from the branches of the interferometer. Once the gate voltage on one of the branches is tuned to achieve an effective symmetry between them, this polarization can be controlled by the electric and/or magnetic fields which determine the spin-orbit interaction strength and the Aharonov-Bohm flux.

Spin filtering in a Rashba–Dresselhaus–Aharonov–Bohm double-dot interferometer

“…We emphasize that the solution is not limited to this model. One can model each QD/QN by an arbitrary number of sites M. This changes only the transmission of the spin-polarized electrons, with no significant effect on the spin filtering conditions and the polarization direction of the outgoing electrons [32].…”

“…Moreover, the transmission of the outgoing spin-polarized electrons can be tuned to unity in a wide range of energies. Recently, we generalized this interferometer by including a possible leakage of electrons out of the interferometer [32]. We have shown that spin filtering is still possible in a non-unitary transport, even though the transmission is inherently less than unity.…”

“…A major advantage of the diamond interferometer is that full spin filtering can be achieved independent of the electron energy. However, the conditions for full spin filtering, independent of the electron energy, require perfect symmetry between the two branches of the interferometer [30,32]. Having fulfilled these symmetry relations, the polarization of the outgoing electrons is independent of energy and completely determined by the AB and AC phases [30,32] (and therefore by the external electric and magnetic fields perpendicular to the interferometer plane).…”

“…Using scattering theory in the framework of the tight-binding formalism, we calculate the spin-dependent transmission through this interferometer. We employ a one-dimensional tight-binding model, assuming that the interferometer is composed of quasi one-dimensional wires [30,32].…”

Spin filtering in all-electrical three-terminal interferometers

“…44 broke the unitarity of the two-terminal scattering matrix by adding leakage of electrons into additional reservoirs. 47,48 As we argue below, the results of these calculations apply only when the additional (leakage) leads are held at the same chemical potential as the output lead. Unlike Ref.…”