  Dielectric interfaces critical for metal-oxide-semiconductor (MOS) electronic
devices, such as the Si/SiO$_2$ MOS field effect transistor (MOSFET), possess
trap states that can be visualized with electrically-detected spin resonance
techniques, however the interpretation of such measurements has been hampered
by the lack of a general theory of the phenomena. This article presents such a
theory for two electrical spin-resonance techniques, electrically detected
magnetic resonance (EDMR) and the recently observed near-zero field
magnetoresistance (NZFMR), by generalizing Shockley Read Hall trap-assisted
recombination current calculations via stochastic Liouville equations. Spin
mixing at this dielectric interface occurs via the hyperfine interaction, which
we show can be treated either quantum mechanically or semiclassically, yielding
distinctive differences in the current across the interface. By analyzing the
bias dependence of NZFMR and EDMR, we find that the recombination in a
Si/SiO$_2$ MOSFET is well understood within a semiclassical approach.
