Spin Tunneling through an Indirect-Gap semiconductor Barrier

We study the spin dependent tunneling of electrons through an indirect conduction minimum of a zinc-blende semiconductor and show that both the transmission coefficient as well as the spin polarization can be substantially large at the same time, unlike the case for tunneling through a direct minimum.$^1$ The spin polarization is calculated using a simple barrier tunneling model. The parameter describing the linear $k$ spin splitting for the indirect minimum is computed using density- functional method. The basic difference is the linear $k$ spin splitting for the indirect minimum, as opposed to the Dresselhaus $k^3$ splitting for the direct minimum at the $\gamma$ point. \newline \newline $^1$V. I. Perel, S. A. Tarasenko, and I. N. Yassievich. Phys. Rev. B {\bf 67}, 201304 (2003).