Mixed configuration ground state in Iron(II) Phthalocyanine

Abstract

We calculate the angular dependence of the x-ray linear and circular dichroism at the $L_{2,3}$ edges of $\alpha$-Fe(II) Phthalocyanine (FePc) thin films using a ligand field model with full configuration interaction. We find the best agreement with the experimental spectra for a mixed ground state of ${}^3{E}_g(a_{1g}^2{e}_g^3{b}_{2g}^1)$ and ${}^3{B}_{2g}(a_{1g}^1{e}_g^4{b}_{2g}^1)$ with the two configurations coupled by the spin-orbit interaction. The ${}^3{E}_g(b)$ and ${}^3{B}_{2g}$ states have an easy axis and plane anisotropies, respectively. Our model accounts for an easy-plane magnetic anisotropy and the measured magnitudes of the in-plane orbital and spin moments. The proximity in energy of the two configurations allows a switching of the magnetic anisotropy from easy plane to easy axis with a small change in the crystal field, as recently observed for FePc adsorbed on an oxidized Cu surface. We also discuss the possibility of a quintet ground state (${}^5{A}_{1g}$ is 250~meV above the ground state) with planar anisotropy by manipulation of the Fe-C bond length by depositing the complex on a substrate that is subjected to a mechanical strain.

References in corpus (7)

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• Graphene as a reversible spin manipulator of molecular magnets
• Understanding the Unique Structural and Electronic Properties of SrFeO2
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• Ligand field parameters and the ground state of Fe(II) phthalocyanine

Cited by in corpus (4)

• Observation of Coexistence of Yu-Shiba-Rusinov States and Spin-Flip Excitations
• New Insight into the Ground State of FePc: A Diffusion Monte Carlo Study
• Ab initio theory of graphene-iron(II) phthalocyanine hybrid systems as scalable molecular spintronics
• Control of molecular orbital ordering using a van der Waals monolayer ferroelectric