Intrinsic Decay of Spin Currents: The Spin Coulomb Drag Effect

Abstract

We review the properties of spin Coulomb drag, which describes the effects of the “friction” arising between different spin-polarized carrier populations when they travel with different average velocities. We compare this effect with the ordinary Coulomb drag between separate slabs underlining some important differences related to the form of the Coulomb interaction in the two cases. We show that the spin-transresistivity, a measure of the spin Coulomb drag effect, can become as high as 10−2–10−3 Ω cm in three dimensions and of the order of several kiloohms in two dimensions. We finally underline that, in some realistic systems, the spin transresistivity can become comparable to the usual Drude resistivity.