Spin and Charge Currents from Stern-Gerlach-Like Forces

In this work we study the influence of non-uniform magnetic fields on spin and charge dynamics in semiconductors. To do so, we solve a set of drift-diffusion equations which incorporate effects of electric and magnetic fields, spin relaxation, and field gradients. In some simple scenarios we find analytic solutions for both time-dependent and steady state conditions. More generally, we numerically solve a set of coupled ordinary or partial differential equations. Our conclusions are that both charge and pure spin currents can be generated by the Stern-Gerlach-like forces arising from a magnetic field with a constant gradient. Lastly, we introduce spin Hall and inverse spin Hall effects into our model to determine how they may amplify or obscure the Stern-Gerlach-like driven effects.