Regensburg 2013 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 30: Correlated Electrons: Quantum Impurities, Kondo Physics
TT 30.6: Vortrag
Dienstag, 12. März 2013, 10:45–11:00, H21
Hydrogen-induced Kondo effect for single Co atoms adsorbed on Pt(111) — Quentin Dubout, Fabian Calleja, Markus Etzkorn, •Fabio Donati, Laurent Claude, Anne Lehnert, Pietro Gambardella, and Harald Brune — Institute of Condensed Matter Physics (ICMP),Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
We report on 0.4 K STM measurements revealing the H-induced Kondo effect for single Co atoms on a Pt(111) surface. Clean Co/Pt(111) has S = 1 and out-of-plane anisotropy [1], its ground state is m = ± 1 and therefore cannot exhibit a first order Kondo effect [2]. Upon H2 adsorption, or upon exposing the sample to the residual gas of the UHV chamber, we find two hydrogenated species, CoH and CoH2. Both complexes show a number of differential conductance steps, some shift upon isotope substitution, revealing their vibrational origin. The most interesting feature is that CoH2 presents a large conductance peak at the Fermi level. It shows the thermal broadening and magnetic field splitting identifying its origin as the Kondo effect. The CoH2 complex has S = 3/2 and in-plane hard axis. To our knowledge, this is the first observation of adsorbate induced Kondo effect. In our case, the adsorbate changes the spin and the magnetic anisotropy energy.
[1] P. Gambardella et al., Science 300, 1130 (2003).
A. F. Otte et al., Nat. Phys. 4, 847 (2008).