Temperature dependence of the spectral profile of the Yosida-Kondo resonance for a single magnetic atom adsorbed on a metal surface

摘要

The Kondo temperature T_K, for a system consisting of a magnetic atom adsorbed on a non-magnetic metal surface, is usually determined experimentally from the corresponding energy width of the dI/dV(V) spectra, at the vicinity of the Fermi level E_F. However, the dI/dV(V) spectra could exhibit symmetric or asymmetric, dip or peak structures around V = 0, depending on the Fano parameter q (which gives us a measure of the spatial extent of the wavefunction function for the localized orbital—how far it protrudes—out of the surface, for a particular adsorbate-metal system). Determining the corresponding Kondo temperature T_K for a magnetic adsorbate on a metal surface system is non-trivial and not so straightforward. Here, we propose another means to experimentally determine T_K, and to check that the resonance observed experimentally does have the temperature dependence characteristic of the Kondo effect, i.e., by measuring the peak height of the second-derivative of the dI/dV(V) spectra at the vicinity of E_F—d~2I/dV~2(V). We also provide a brief history of the Kondo effect and the events leading up to this present study.