When Molecular Dimerization Induces Magnetic Bi‐Stability at the Metal–Organic Interface

Abstract

2D metal-organic frameworks have been recently proposed as a flexible platform for realizing new functional materials including quantum phases. Here, we present a method to create metal-organic dimer complexes by on-surface assembly on a metal substrate using low-temperature scanning tunneling microscopy (STM) and spectroscopy (STS). We demonstrate that a dimer of Mn-Phthalocyanine (MnPc) 2 on a Ag(111) surface can be switched between two stable configurations upon a small conformational change controlled by STM manipulation. By means of density-functional theory calculations, it is found that the two conformations correspond to an antiferromagnetic (AFM) and a ferromagnetic (FM) state respectively. Directly coordinated Mn atoms of the dimer lead to an AFM-coupling whereas indirectly coordinated (shifted) Mn atoms lead to a FM-coupling. Rarely seen in a molecular-dimers with transition-metal atoms, the FM-AFM-FM transition is thus readily on-surface accessible. Furthermore, the two configurations of the switch are easily identified by their Kondo states, opening interesting routes in terms of both, writing (FM versus AFM states) and reading. These results pave the experimental route toward dimer-based materials with complex magnetic structures of potential interest for application in spintronics, logics and computing.

Hierarchical Self-Assembly and Conformation of Tb Double-Decker Molecular Magnets: Experiment and Molecular Dynamics

“…All STM/STS data were acquired at 4.5 K. STS spectra were measured using lock-in detection, with a modulation between 1 mV and 10 mV (rms) depending on the features to be resolved. Manipulation by means of the STM tip of this category of molecules was described earlier [17][18][19].…”