Magnetic subunits within a single molecule–surface hybrid

Magnetic molecule–surface hybrids are ideal building blocks for molecular spintronic devices due to their appealing tailorable magnetic properties and nanoscale size. So far, assemblies of interacting molecular-surface hybrids needed for spintronic functionality were generated by depositing aromatic molecules onto transition-metal surfaces, resulting in a random arrangement of hybrid magnets due to the inherent and strong hybridization.

Here, we demonstrate the formation of multiple intramolecular subunits within a single molecule–surface hybrid by means of spin-polarized scanning tunneling microscopy experiments and ab initio density functional theory calculations. This novel
effect is realized by depositing a polycyclic aromatic molecule on a magnetic surface. A highly asymmetric chiral adsorption position induces different structural, electronic, and magnetic properties in each aromatic ring of the molecule. In particular, the induced molecular spin polarization near the Fermi energy varies among the rings due to site- and spin-dependent molecule–surface hybridization.

Our results showcase a possible organic chemistry route of tailoring geometrically well defined assemblies of magnetically distinguishable subunits in molecule–surface hybrids.

Figure:(a) Topview of the relaxed adsorption geometry of TPT on 2 ML Fe/W(110) determined by DFT. (b) STM topography image of TPT on 2 ML Fe/W(110) taken at VBias=-100mV and IT=1nA. (c) measured spin polarization (SP) map at VBias=-100mV. (d) Assignment of the 4 magnetic subunits and the associated exchange couplings constants between the subsunits J1x and their enviroment Jxcs (x=1,2,3,4) .

Volkmar Heß, Rico Friedrich, Frank Matthes, Vasile Caciuc, Nicolae Atodiresei, Daniel E. Bürgler, Stefan Blügel and Claus M. Schneider
Magnetic subunits within a single molecule–surface hybrid
New Journal of Physics 19 053016 (2017)