(Color online) Spin-up and spin-down transmission probabilities as a function of the Rashba strength for M = 10 and two values of the Fermi energy. The solid and dotted lines show for E/t = 0.29 and E/t = −0.29, respectively. The dashed line represents for E/t = −0.29. The solid and dashed lines fall on each other. Inset: Schematic representation of the channel for M = 10.