Abstract
We study the the spin polarization in nano-wire in presence of Rashba spin orbit interaction in ballistic regime. Analytically, we calculate the allowed eigenstates in the wire and their corresponding out-of-plane component of spin distribution. Among the out-of-plane component of spin for the eigenstates, we find the parity effect between every other states. From the symmetry arguments, we show that the out-of-plane component of spin must be anti-symmetric in the lateral direction, and that it is non-zero only when the time-reversal symmetry property of the system is broken. We also study the system numerically with Open-boundary Planar Supercell Stack Method. The numerical results show that the spin accumulation remains in the presence of weak disorder potential but is diminished when the disorder potential is large. With the existence of impurity in the system, we show that it does excite out-of-plane spin component unlike the prediction of the general scattering analysis. In the presence of surface roughness, the spin accumulation is pushed away from the edges and the amplitude of the accumulation decrease as the roughness becomes strong.