Scanning Tunneling Microscopy Study of the Spin Hall Effect in Platinum and Highly Resistive Tungsten Films

The results of a nanoscale experimental study of the spin Hall effect in platinum and highly resistive tungsten films are reported. These results are obtained by using scanning tunneling microscopy based measurements with tungsten and iron-coated tungsten tips. These measurements reveal an appreciable asymmetry of tunneling currents observed by changing the polarity of tunneling voltages or the direction of electric currents through the films. This asymmetry is a manifestation of accumulations of spin-polarized electrons on conducting film boundaries occurring as a result of the spin Hall effect.