Uniaxial 2D Superlattice of Fe₄ Molecular Magnets on Graphene

Abstract

We demonstrate that electrospray deposition enables the fabrication of highly periodic self-assembled arrays of FeH single molecule magnets on graphene/Ir(111). The energetic positions of molecular states are probed by means of scanning tunneling spectroscopy, showing pronounced long- and short-ranged spatial modulations, indicating the presence of both locally varying intermolecular as well as adsorption-site dependent molecule-substrate interactions. From the magnetic field dependence of the X-ray magnetic circular dichroism signal, we infer that the magnetic easy axis of each FeH molecule is oriented perpendicular to the sample surface and that after the deposition the value of the uniaxial anisotropy is identical to the one in bulk. Our findings therefore suggest that the observed interaction of the molecules with their surrounding does not modify the molecular magnetism, resulting in a two-dimensional array of molecular magnets that retain their bulk magnetic properties.

Tip‐Induced Inversion of the Chirality of a Molecule's Adsorption Potential Probed by the Switching Directionality

“…The purity of the final material was verified by nuclear magnetic resonance spectroscopy and mass spectrometry. The clean Ag(111) single crystal (Surface Preparation Laboratory) surface was prepared by repeated cycles of Ar + sputtering and subsequent annealing to about 890 K. Electrospray deposition of TAT molecules on the clean Ag(111) surface was performed as described elsewhere 27,28. The sample was kept at room temperature during deposition, and then transferred into the cryogenic STM (Omicron Nanotechnology GmbH) operated at temperatures of 5–6 K. STM measurements were carried out in the constant‐current mode using grinded and polished PtIr tips (Nanoscore GmbH).…”

“…In this work, we investigate triazatruxene (TAT) molecules on a Ag(111) surface deposited by the electrospray method 27,28 . Figure a shows a large‐scale scanning tunneling microscopy (STM) image of individual TAT molecules on Ag(111).…”

“…Its controlled and precise manipulation will ensure the possibility of tuning the number of accessible states and switching rates, allowing the system to be reliably programmed.In this work, we investigate triazatruxene (TAT) molecules on a Ag(111) surface deposited by the electrospray method. [27,28] Figure 1a shows a large-scale scanning tunneling microscopy (STM) image of individual TAT molecules on Ag(111). The observed intramolecular contrast suggests the presence of several adsorption configurations, which will be discussed in the following.…”

Propeller‐Shaped Fe4 and Fe3M Molecular Nanomagnets: A Journey from Crystals to Addressable Single Molecules

“…However, some 3 R complexes are also suitable for electrospray deposition (ESD) or even thermal sublimation in UHV. The derivative with R = H, for instance, was deposited by ESD on hexagonal boron nitride/Rh(111) and graphene/Ir(111); because molecules of 3 H are disc‐shaped, they physisorb with their threefold axis along the surface normal to give highly ordered monolayers , . A protruding R = Ph group enhances thermal stability thus allowing deposition by thermal sublimation.…”

“…A softer and more controlled approach used to deposit Fe 4 SMMs on substrates is ESD with mass selection , . In this case, STM images of monolayers of 3 H deposited on substrates such as hexagonal boron nitride/Rh(111) and graphene/Ir(111) clearly confirmed the absence of contaminants.…”