Rashba spin−orbit coupling effect on tunneling time in semiconductor spintronic junctions

Based on the transfer-matrix method and the group velocity concept, we investigate theoretically the spin tunneling time through single and double barriers of diluted magnetic semiconductor structures in the presence of the Rashba spin−orbit coupling (RSOC) effect. The calculation of transmission probability is based on an effective mass quantum-mechanical approach in the presence of an external magnetic field applied along the growth direction of the junction. The results show that the RSOC has great different influence on spin-dependent tunneling time of electrons with spin up and spin down in these structures. We also study the effect of zero-field conduction band offset on spin-dependent transmission properties. It is found that in the presence of RSOC and a positive zero-field conduction band offset as high as 10 meV, the results show a high degree of spin polarization and spin separation in the tunneling time in the considered system and this aspect may be utilized in designing new spin filter devices.