Experimental observation of coupled valley and spin Hall effect in p-doped WSe2 devices

It is generally accepted that perpendicular magnetic anisotropy (PMA) magnets are preferred over in-plane magnetic anisotropy (IMA) magnets in data storage applications owing to their large thermal stability even at ultra-scaled dimensions. To efficiently and deterministically switch a PMA, out-of-plan spin current is required. However, conventional giant spin Hall effect (GSHE) materials only produce spin currents with in-plane polarization. Our work, on the other hand, demonstrated for the first time that out-of-plane spin currents can indeed be generated by applying electric filed to monolayer WSe(2)at room temperature and the spin information was detected by a graphene channel. Supported by theoretical calculations, we found that the interfacial polarization between graphene and WSe(2)to be similar to 38% assuming the ferromagnetic detector's polarization efficiency to be similar to 4%. Moreover, the spin polarization is determined by the polarity of the applied electric field.