Scanning tunneling spectroscopy study of Fe(001) using nonmagnetic W- and Fe-evaporated probe tips

The differential conductivity (dI/dV) spectra of Fe(001) film, together with the topographic image, wire measured at room temperature using ferromagnetic Fe and non-magnetic W probe tips. A narrow peak was observed at 0.3 V in the dI/dV spectrum using a W tip, which coincides with the surface state in the minority spin band predicted by a theoretical calculation. On the other hand, we found a pronounced peak at 0.7 V in the tunneling spectra using a Fe-evaporated probe tip with all intense and broad feature, which cannot be explained by the calculation The enhancement of spin-polarized tunneling in an empty sample slate might occur in the case bf a Fe tip.