Spin-orbit-induced torque in a collinear spin valve: A possible route to design fast magnetic memory

We argue and show that spin-orbit (SO) interaction can induce a torque for the collinear configuration of spin valve structure (F1/2DEG/F2). Further, it is argued that this SO-induced torque can induce magnetization reversal even in collinear spin valves. The theoretical estimates of this effect that are made are well within the reach of present day experimental observations. In addition, it is shown that the same mechanism allows one to increase the purity of the outgoing current and produces entangled spin states essential for quantum computation. A scattering theory for the spin-density matrix is developed. Using this theory, the SO-induced torque and the associated von Neumann entropy are studied quantitatively.