Finite Width and Local Field Corrections to Spin Coulomb Drag in a Quasi-Two-Dimensional Electron Gas

We investigate the effect of many-body electronic correlations on spin Coulomb drag (SCD) beyond the random phase approximation (RPA). We make use of the fully spin-resolved static and dynamical many-body local field factors of the two-dimensional electron gas (2DEG) to improve the calculations of the particle-hole and plasmon-mediated contributions to the SCD. Also, we incorporate in our calculations the transverse thickness of the quantum well in which the 2DEG resides. In contrast to the conventional charge Coulomb drag, in the SCD the effect of layer thickness is significant even at relatively high temperature and densities. The final outcome of our study is that the enhancement of the spin drag caused by many-body local field effects largely compensates the reduction of the effect coming from the finite well thickness, restoring good agreement with the experimental observations by C.P. Weber et al., Nature 437 (2005) 1330