Modeling spin transport with current-sensing spin detectors

The impulse response (or ``Green's function'') of a current-sensing spin detector is derived analytically by incorporating the proper boundary conditions. This result is also compared to a Monte Carlo simulation (which automatically takes the proper boundary conditions into account) and an empirical spin transit time distribution obtained from experimental spin precession measurements. In the strong drift-dominated transport regime, this spin \emph{current} impulse response can be approximated by multiplying the spin \emph{density} impulse response by the average drift velocity. However, in weak drift fields, large modeling errors up to a factor of 3 in most-probable spin transit time can be incurred unless the full spin current Green's function is used.