Substitutional Ag defects in the top-most atomic layer of the Cu(111) act as pinning centers for Co adatoms without affecting their electronic nor magnetic properties (the Kondo resonance remains essentially the same). The Ag impurities are hardly detectable in topographic imaging as they produce no standing-wave pattern and the dI/dV recorded above them is hardly different from that of the clean surface.
COBISS.SI-ID: 23629351
Phase diagram of 0- and pi-junction regimes of Josephson supercurrent is established for a double quantum dot in contact with two superconducting leads. An island of pi-phase appears in the range where all three competing interactions (superexchange, Kondo screening, superconductivity) are equally strong.
COBISS.SI-ID: 23965735
We show that the results of the NRG method agree with an exact simulation using the Quantum Monte Carlo method, while the Bethe Ansatz results do not agree. We prospose that the singular behavior is the consequence of the "dark state" which is asymptotically decoupled from the rest of the system.
COBISS.SI-ID: 25585703