Orbital symmetry of the Kondo state in adsorbed FePc molecules on the Au(110) metal surface

The Kondo ground state can arise in surface-supported organometallic systems, such as the 3d transitionmetal phthalocyanines, as a result of the hybridization of the3d localized orbitals with the underlying metal substrateelectrons. Low-temperature scanning tunneling spectroscopycan identify the Kondo states as a zero-bias anomaly in thedifferential conductance curves, often localized in closeproximity with the 3d metal center. However, the informationon the symmetry of the Kondo state, on the exact shape of thespectral function, and on the magnetic state is generallymissing from the experimental data. We apply complementarytechniques, i.e., scanning tunneling spectroscopy, resonantphotoemission spectroscopy, and X-ray magnetic circulardichroism, to identify the Kondo state, the orbital symmetry, and the magnetic moment of Fe-Phthalocyanine chains formedby two structural phases with increasing molecular density:first×5 and at higher coverage×7 FePc ordered chain structuresassembled on the Au(110) surface. The experimental data suggest the presence of a Kondo state only in the×5 phase, at lowermolecular density, with a Kondo temperature of about 60 K, having parent states with thedxz,dyzsymmetry, that cancels themagnetic moment of the molecules at low temperatures.