S. Souma, A. Sawada, H. Chen, Y. Sekine, M. Eto, T. Koga
PHYSICAL REVIEW APPLIED 4 3 2015年09月
[査読有り][通常論文] 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.