Inelastic tunneling spectroscopy for magnetic atoms and the Kondo resonance

EDITH C. GOLDBERG; F. FLORES

JOURNAL OF PHYSICS CONDENSED MATTER

IOP PUBLISHING LTD

Lugar: Londres; Año: 2013 vol. 25 p. 1 - 7

0953-8984

The interaction between a single magnetic atom and the metal environment (including a magnetic field) is analyzed by introducing an ionic Hamiltonian combined with an effective crystal field term, and by using a Green-function Equation of Motion method. This approach describes the inelastic electron tunneling spectroscopy and the Kondo resonances as due to atomic spin fluctuations associated with electron co-tunneling processes between the leads and the atom. We analyze in the case of Fe on CuN the possible spin fluctuations between states with S=2 and S=3/2 or 5/2 and conclude that the experimentally found asymmetries in the conductance with respect to the applied bias,  and its marked structures , are well explained by the 2«3/2 spin fluctuations. The case of Co is also considered and shown to present, in contrast with Fe, a resonance at the Fermi energy corresponding to a Kondo temperature of 6K.