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Joerg Kroeger

Publications and source records attributed to Joerg Kroeger.

2 recordsLinked to original sources

Evolution of unoccupied resonance during the synthesis of a silver dimer on Ag(111)

Silver dimers were fabricated on Ag(111) by single-atom manipulation using the tip of a cryogenic scanning tunnelling microscope. An unoccupied electronic resonance was observed to shift toward the Fermi level with decreasing atom-atom distance as monitored by spatially resolved scanning tunnelling spectroscopy. Density functional calculations were used to analyse the experimental observations and revealed that the coupling between the adsorbed atoms is predominantly direct rather than indirect via the Ag(111) substrate.

cond-mat.mtrl-sci

Quantum modulation of the Kondo resonance of Co adatoms on Cu/Co/Cu(100)

Low-temperature scanning tunneling spectroscopy reveals that the Kondo temperature T_K of Co atoms adsorbed on Cu/Co/Cu(100) multilayers varies between 60 K and 134 K as the Cu film thickness decreases from 20 to 5 atomic layers. The observed change of T_K is attributed to a variation of the density of states at the Fermi level ρ_F induced by quantum well states confined to the Cu film. A model calculation based on the quantum oscillations of ρ_F at the belly and the neck of the Cu Fermi surface reproduces most of the features in the measured variation of T_K.

cond-mat.mes-hall