Switching the Spin on a Ni Trimer within a Metal–Organic Motif by Controlling the On-Top Bromine Atom

Abstract

Controlling the spin of metal atoms embedded in molecular systems is a key step towards the realization of molecular electronics and spintronics. Many efforts have been devoted to explore the influencing factors dictating the survival or quenching of a magnetic moment in a metal-organic molecule, and among others, the spin control by axial ligand attachments is most promising. Herein, from the interplay of highresolution STM imaging/manipulation and STS measurements together with DFT calculations, we successfully demonstrate that a Ni trimer within a metal-organic motif acquires a net spin promoted by the adsorption of an on-top Br atom. The spin localization in the tri-metal centers bonded to Br was monitored via the Kondo effect.The removal of the Br ligand resulted in the switch from a Kondo ON to a Kondo OFF state. The magnetic state induced by the Br ligand is theoretically attributed to the enhanced Br 4p z and Ni 4dz 2 states due to the charge redistribution. The manipulation strategy reported here provides the possibility to explore potential applications of spin-tunable structures in spintronic devices.

Reaction on a Rink: Kondo-Enhanced Heterogeneous Single-Atom Catalysis

“…Experimentally, it has been shown that the Kondo spin-screening can be switched on and off by chemical doping. [23][24][25] A reduced barrier height usually means enhanced kinetics. Thus, with T s being much lower than the temperature of reactant species (T r ), the accelerated heterogeneous reaction is reminiscent of skating on an ice rink.…”

“…21 Extensive works have been carried out to fine-tune the strength of Kondo screening by adjusting the microenvironment of the TM adatom. [22][23][24][25] However, the thermochemical change associated with the Kondo spin-screening phenomenon and its implication to the chemical reactions catalyzed by the TM adatom are largely unexplored.…”

Reaction on a Rink: Kondo-Enhanced Heterogeneous Single-atom Catalysis

“…Experimentally, it has been shown that the Kondo spin-screening can be switched on and off by chemical doping. [31][32][33] A reduced barrier height usually means enhanced kinetics. Thus, the heterogeneous reaction could be effectively accelerated by tuning T s to be much lower than the temperature of reactant species (T r ), the accelerated heterogeneous reaction is reminiscent of skating on an ice rink.…”

“…29 Extensive works have been carried out to fine-tune the strength of Kondo screening by adjusting the microenvironment of the TM adatom. [30][31][32][33][34] However, the thermochemical change associated with the antiferromagnetic Kondo spin-screening phenomenon and its implication to the chemical reactions catalyzed by the TM adatom are largely unexplored.…”

Molecular molds for regularizing Kondo states at atom/metal interfaces

“…Physically, the Kondo states originate from the screening of the local spin of d electrons on the TM atom by the spins of itinerant electrons in the metal substrate. Recently, the precise control and tuning of Kondo states have become a focus of experimental efforts [10][11][12][13][14][15][16][17] . However, it is generally observed that the Kondo features vary greatly with the local chemical environment surrounding the TM atom, such as the coordinating ligands, the chemical dopants, the metal substrate, etc.…”