Hybridized Kondo State Formed by π Radical Assemblies

Abstract

We study the spin state of the π radical assemblies, which are created through converting nonmagnetic terbium (2,3,7,8,12,13,17,18-octaethylporphyrinate) (2,3,7,8,12,13,17,18-octaethylporphyrindiate) (Tb­(Hoep)­(oep)) selectively either into [Tb­(oep)2] or deethyl-[Tb­(oep)2] radical molecule by removing the H atom and further ethyl group, with the injection of tunneling electrons using a scanning tunneling microscope. The Kondo resonance, formed by screening the radical spin by the conduction electron, shows the dip and peak shapes for [Tb­(oep)2] or deethyl-[Tb­(oep)2], respectively, due to the difference in the coupling between the two oep ligands. When these two types of molecules are created next to each other, the Kondo resonance appears as a mixture of the peak and dip at the interface of the two. This is interpreted as the result of the hybridization of the two different π radical orbitals, suggesting a possible control of the Kondo state by designing the molecular orbitals.

Chemical Way to Tune Spin Excitation of Magnetic Atoms in Sierpiński Triangles

“…Understanding fractal structures at the molecule scale is of great importance in both fundamental science and applied technology. − Sierpiński triangles (STs), one representative type of fractal structures, have been constructed on single-crystalline surfaces via halogen bonding, metal–organic coordination bonding, − hydrogen bonding, and covalent bonding interactions. − Especially, metal–organic STs up to fifth-order and large-scale two-dimensional (2D) crystals with STs as building blocks have been prepared recently. , STs are theoretically predicted to have exotic mechanical, electronic, and magnetic properties but not experimentally realized. − It is of high value to use the prepared STs to explore their properties. As a first step, the spin excitation of magnetic STs will be investigated by low-temperature scanning tunneling microscopy (STM) for its capability of spin characterization at the single-atom level. − …”

Ligand Rotation Induced Oxidation State Change and Spin Appearance of the Bis(phthalocyaninato)cerium (CePc2) Molecule on the Au(111) Surface

“…In our previous study, we showed the spin state of the π radical assemblies using Tb(oep) 2 (oep = 2,3,7,8,12,13,17,18-octaethylporphyrinate) and demonstrated that the presence of the neighboring with the π radical spin changes the Kondo state of Tb(oep) 2 . 61 We noticed that the effect is local, and the strongest variation appears at the lobe close to the interface of the two molecules. Thus, we investigated the molecule of θ = 45°at the edge of the monolayer island and measured the STS at the lobe of the interface.…”

“…Instead, we measure the θ = 45° molecule attached with two CePc 2 molecules. In our previous study, we showed the spin state of the π radical assemblies using Tb­(oep) 2 (oep = 2,3,7,8,12,13,17,18-octaethylporphyrinate) and demonstrated that the presence of the neighboring with the π radical spin changes the Kondo state of Tb­(oep) 2 . We noticed that the effect is local, and the strongest variation appears at the lobe close to the interface of the two molecules.…”

“…The interference of the two makes the shape of the Fano resonance . We fitted the peak using the Fano function, while Frota line was used in more accurate analysis. , We described the fitting of the STS spectrum with the Fano function in our previous report . In addition, the shape and intensity depend on the chemical environment.…”

“…59,60 We described the fitting of the STS spectrum with the Fano function in our previous report. 61 In addition, the shape and intensity depend on the chemical environment. The Kondo peak might be absent if the coupling with the substrate weakens.…”