Persistent Spin Current in a Quantum Wire with Weak RashbaSpin–Orbit Coupling

Abstract

We theoretically investigate the spin current for a parabolicallyconfined semiconductor heterojunction quantum wire with weak Rashbaspin–orbit coupling by means of the perturbation method. By analyticalcalculation, it is found that only two components of spin currentdensity is non-zero in the equilibrium case. Numerical examples havedemonstrated that the spin current of electron transverse motion is10−3 times that of electron longitudinal motion. However, theformer one is much more sensitive to the strength of Rashba spin–orbitcoupling. These results may suggest an approach to the spin storagedevice and to the measurement of spin current through its inducedelectric field.