||Spin Blocker Using the Interband Rashba Effect in Symmetric Double Quantum Wells
Souma, S. ,
Sawada, A. ,
Chen, H. ,
Sekine, Y. ,
Eto, M.Koga, T.
, p.34010 , 2015-09-29 , American Physical Society
We propose a lateral spin-blockade device that uses the interband Rashba effect in a symmetric double quantum well (QW), where the Rashba effect in the conventional sense vanishes because of its inversion symmetry. The interband Rashba effect manifests itself in the off-diagonal term (represented by the parameter eta) in the QW space using the bonding and antibonding basis [Esmerindo Bernardes, John Schliemann, Minchul Lee, J. Carlos Egues, and Daniel Loss, Phys. Rev. Lett. 99, 076603 (2007)]. In such a system, spin selection is possible by tuning the device length, gate electric field and in-plane magnetic field. We particularly show illustrative mechanisms using a one-dimensional model with k = (k(F), 0), where the selected spin can be blocked completely in the presence of the in-plane magnetic field. While the inclusion of the finite k(y) and/or the gate electric field deteriorates the spin polarization P, finite values remain for P (P>11%). Our proposal can also be regarded as an effective way of enhancing a variation of the Rashba-Edelstein effect, the generation of bulk spin polarization by electric current, based on semiconductor band engineering technology.