Conductance Oscillations in Spin Field-Effect Transistors

摘要

＜正＞ Ballistic spin transport in spin field-effect transistors is studied by taking into account the Rashba spinorbit coupling, interracial scattering, and band mismatch. It is shown that the spin conductance oscillation with the semiconductor channel length is a superimposition of the Rashba spin precession and spin interference oscillations. They have different oscillation periods π/kR and π/k with kR the Rashba wavevector and k the Fermi wavevector of thesemiconductor channel, and play different parts of slow and rapid oscillations, depending upon the relative magnitude ofπ/kR and π/k. Only at k=kR does the spin conductance exhibit oscillations of a single period. Two types of different behaviors of the tunnelling magnetoresistance are discussed.