Spin-polarized electronic current in resonant tunneling heterostructures

The spin-dependent tunneling phenomenon in symmetric and asymmetric resonan t semiconductor heterostructures is employed in a theoretical study to inve stigate the output tunnel current polarization at zero magnetic field. A si mple model of the resonant tunneling structures and a simple one-electron b and approximation with spin-orbit interaction are used in this work. It is shown that asymmetry in the electron distribution at the electrode regions provides spin-polarized tunnel current. An approach to optimize this spin-d ependent effect is explored theoretically. In asymmetric resonant tunneling structures, we estimate theoretically that the polarization can reach 40% with a moderate applied electric field. (C) 2000 American Institute of Phys ics. [S0021- 8979(00)09501-3].