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 WSe2 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 WSe2 to be^38%assuming the ferromagnetic detector's polarization efficiency to be^4%.Moreover,the spin polarization is determined by the polarity of the applied electric field.