Anisotropic spin diffusion in a semiconductor quantum well

We show that spin diffusion of an inhomogeneous spin density distribution in an asymmetric zinc-blende semiconductor quantum well is anisotropic in coordinate space, if the D'yakonov-Perel' spin relaxation mechanism is dominant. This anisotropy depends on the relation between the Dresselhaus and Rashba contributions to the spin splitting and reaches its maximum when the both contributions are equal in magnitude. Under this condition the temporal behavior of the spin density strongly depends on the relation between the initial spatial extent of the spin packet and spin diffusion length.