Dresselhaus spin-orbit effect on traversal time in ferromagnetic/semiconductor/ferromagnetic heterojunctions

Abstract

Taking into consideration the Dresselhaus spin-orbit interaction, we study theoretically the transmission coefficients and the traversal time of electrons tunneling through $\mathrm{Fe}∕\mathrm{Ga}\mathrm{Sb}∕\mathrm{Fe}$ and $\mathrm{Fe}∕\mathrm{In}\mathrm{Sb}∕\mathrm{Fe}$ heterostructures. There is a common characteristic for the two different structures, i.e., the transmission coefficients, whether for spin-up spin-down electrons, show obvious resonant features when electrons tunnel through the two heterostructures. We further see that as the length of the semiconductor increases the traversal time of both spin-up and spin-down electrons does not increase linearly but shows steplike behavior: the quantum size effect. Furthermore, we show that the Dresselhaus spin-orbit coupling, unlike Rashba spin-orbit coupling, does not prolong the traversal time of electrons. Because of the different effect of the Dresselhaus spin-orbit coupling on the traversal time of spin-up and spin-down electrons, the difference in the dwell time between spin-up and spin-down electrons can become greater as the length of the semiconductor changes. This is helpful from the device point of view for differentiating spin-up and spin-down electrons and achieving high spin polarizations.