Electric Field Effect on Spin Diffusion in a Semiconductor Channel

In the diffusive regime, the accumulated spins diffuse out symmetrically in both directions of the InAs channel and the spin signal exponentially decays with the distance. However, considering spin drift induced by the applied electrical current, the spin diffusion occurs in an asymmetric manner. Nonlocal measurements of a lateral spin-valve structure show that the amount of spin polarized electron depends on the direction of the electric field. The magnitude of the nonlocal signal difference due to the bias-current-induced drift effect diminishes from 5.6 mOmega at T=20 K to close to zero at T=300 K.