Modelling & Simulation


Tailoring the magnetic ground state of a metal-molecule complex dimer on a substrate by chemical interactions

Frithjof Anders, Physics Department/TU Dortmund, Dortmund, Germany

Rather than relying on the magnetic exchange interaction to tailor the magnetic properties of a nanostructure, we utilise non-magnetic chemical interaction between the constituents of the nanostructure to achieve the same goal. Our approach is crucially based on spin-moment carrying orbitals that are extended in space and therefore allow the direct coupling of magnetic properties to wave function overlap. We demonstrate the approach for a dimer of metal-molecule complexes on the Au(111) surface. Changing the wave-function overlap between the two monomers, we tune the surface-adsorbed dimer through a quantum phase transition from an underscreened triplet to a singlet ground state, with one configuration being located extremely close to a quantum critical point.

We demonstrate the predicting power of our combined density functional and numerical renormalization group approach for simulations in materials science by a quantitativ analysis of the measured scanning-tunneling microscope spectra including their temperature dependency.

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