Conductance through a Ti-atom impurity in Ag(100) and Au(111):

M. A. ROMERO; C. S. GOMEZ CARRILLO; F. FLORES; EDITH C. GOLDBERG

PHYSICAL REVIEW B

AMER PHYSICAL SOC

Lugar: New York; Año: 2013 vol. 87 p. 1954191 - 1954197

1098-0121

We describe the interaction between a transition metal atom and a noble metal surface by using an ionic model in which the first Hund?s rule determines the filling of the atom d-levels, and spin fluctuations occur due to the electron exchange between the metal band and atom states. We apply our model to the case of adsorbed Ti atoms on noble metal surfaces (Ag, Au) in which conductance measurements in scanning tunneling microscope (STM) experiments, suggest a mixed valence regime according to the position and width of the atomic resonance. By introducing in our calculation these two parameters, as extracted from the experiment, we satisfactorily reproduce the experimental results in both cases. We find, in the Ag(100) surface, that the conductance spectrum reflects electronic characteristics of the metal surface modified by the presence of the magnetic atom; while in the Au(111) case only the projected density of states on the Ti atom is determining the conductance spectrum shape.