Quantitative And Systematic Analysis Of Bias Dependence Of Spin Accumulation Voltage In A Nondegenerate Si-Based Spin Valve

The dependence of the spin accumulation voltage on the electric bias current for a nondegenerate Si-based spin valve was quantitatively investigated using both experiments and calculations. We attempted to clarify the reason for the disagreement between the experimentally measured values and those calculated using the spin drift-diffusion equation that takes into account the effect of the spin-dependent interfacial resistance of tunneling barriers, which is an important question in semiconductor spintronics. Unlike the case of metallic spin valves, it was found that the bias dependence of the resistance-area product for the ferromagnet/MgO/Si interface causes a conductance mismatch, and this plays a central role in producing the deviation between the experimental and numerical results.