Spin pump induced inverse spin Hall effect observed in Bi-doped n -type Si

An inverse spin Hall effect (ISHE) in $n$-type silicon was observed experimentally when conduction electrons were scattered on the spin-orbit potential of bismuth. The spin current in the silicon layer was generated by excitation of the magnetization precession during ferromagnetic resonance in a thin Permalloy (Py) layer deposited on a Si layer doped by phosphor and bismuth. From the angular dependences of the dc voltage for different $\mathrm{Py}/n$-Si:Bi structures aligned along the [011] or [100] crystal axes, we were able to distinguish the planar Hall effect (PHE) and ISHE contributions. The ISHE dc voltage signal was proportional to the $sin\ensuremath{\theta}sin2\ensuremath{\theta}$ product for the structure aligned to the [011] crystal axis and to $sin\ensuremath{\theta}cos2\ensuremath{\theta}$ for the [100] direction. In addition, the PHE dc voltage was observed for the angles corresponding to the $sin\phantom{\rule{0.16em}{0ex}}2\ensuremath{\theta}$ dependence. This means that for silicon as a many-valley semiconductor, the scattering of spins due to the spin-orbit potential induced by shallow donor in $n$-type material is dependent on the orientation of the valley axes relative to the direction of the magnetic field.