Surface electronic structure of Cr(001): Experiment and theory

Abstract

Low-temperature scanning tunneling microscopy and spectroscopy investigations of the atomically clean Cr(001) surface together with density functional and many-body calculations have been used to study the surface electronic structure. The Friedel oscillations near impurity atoms have been observed and explained within the Fermi surface analysis. A very narrow resonance at $26\phantom{\rule{0.3em}{0ex}}\mathrm{meV}$ above the Fermi level has been observed and the orbital character of corresponding state has been visualized. The experimental data together with many-body calculations give further evidence that the observed resonance is an orbital Kondo resonance formed by two degenerated ${d}_{xz},{d}_{yz}$ surface states. This gives evidence of strong correlation effects on transition metal surfaces.