Sub-molecular modulation of a 4f driven Kondo resonance by surface-induced asymmetry

Abstract

Coupling between a magnetic impurity and an external bath can give rise to many-body quantum phenomena, including Kondo and Hund's impurity states in metals, and Yu-Shiba-Rusinov states in superconductors. While advances have been made in probing the magnetic properties of d-shell impurities on surfaces, the confinement of f orbitals makes them difficult to access directly. Here we show that a 4f driven Kondo resonance can be modulated spatially by asymmetric coupling between a metallic surface and a molecule containing a 4f-like moment. Strong hybridization of dysprosium double-decker phthalocyanine with Cu(001) induces Kondo screening of the central magnetic moment. Misalignment between the symmetry axes of the molecule and the surface induces asymmetry in the molecule's electronic structure, spatially mediating electronic access to the magnetic moment through the Kondo resonance. This work demonstrates the important role that molecular ligands have in mediating electronic and magnetic coupling and in accessing many-body quantum states.

The Kondo resonance line shape in scanning tunnelling spectroscopy: instrumental aspects

“…The Kondo effect arises from the interaction of a localized spin with conduction electrons of a host metal [1,2]. Using scanning tunnelling spectroscopy (STS), one of its fingerprints, a resonance close to the Fermi energy E F , i. e. at zero bias voltage, has been investigated for metal adatoms [3,4,5,6,7,8,9,10] and adsorbed molecules [11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50]. Recent ...…”

On-surface structural and electronic properties of spontaneously formed Tb2Pc3 single molecule magnets

“…The presence of the Kondo effect in TbPc 2 molecules deposited on different metal surface has already been reported by many groups. 6,9,11,15,19,[24][25][26][27]30,35 Consequently we attributed this zero bias anomaly to the Kondo resonance. Our spectroscopic measurements establish that the Kondo resonance appears only for the Tb 2 Pc 3 molecules having the HOMO orbital located closest to the Fermi level.…”

“…16,[32][33][34] One prevalent and widely studied phenomena on TbPc 2 molecules is the selective and controllable presence of a zero-bias Kondo resonance in the dI/dV spectra, localized to the Pc ligand lobes. 6,19,24,26,30,35 The location and strength of the Kondo resonance has been attributed to charge transfer between the substrate and the TbPc 2 molecules. [5][6][7]11,[13][14][15][17][18][19][20]22,[24][25][26][28][29][30]35,36 The Kondo phenomenon is observed in all studies conducted on the monolayer TbPc 2 on Au(111) 19,27 but not on the Ag (111) substrate.…”

“…6,19,24,26,30,35 The location and strength of the Kondo resonance has been attributed to charge transfer between the substrate and the TbPc 2 molecules. [5][6][7]11,[13][14][15][17][18][19][20]22,[24][25][26][28][29][30]35,36 The Kondo phenomenon is observed in all studies conducted on the monolayer TbPc 2 on Au(111) 19,27 but not on the Ag(111) substrate. 24 Nevertheless, in the case of the higher apparent height (i.e.…”

Magnetic anisotropy in surface-supported single-ion lanthanide complexes

“…Whereas the decoupling of the 4f electrons is important for protecting the magnetic state, it is a drawback for fixing the alignment of the anisotropy axis and for addressing and reading out the magnetic state [22]. Hence, it is of interest how strongly 4f electrons can couple to electrons tunneling through individual atoms and molecules on surfaces [23][24][25][26][27].…”