Designing a mechanically driven spin-crossover molecular switch via organic embedding

Abstract

Among spin-crossover complexes, Fe-porphyrin (FeP) stands out for molecular spintronic applications: An intricate, yet favourable balance between ligand fields, charge transfer, and the Coulomb interaction makes FeP highly manipulable, while its planar structure facilitates device integration. Here, we theoretically design a mechanical spin-switch device in which external strain triggers the intrinsic magneto-structural coupling of FeP through a purely organic embedding. Exploiting the chemical compatibility and stretchability of graphene nanoribbon electrodes, we overcome common reliability and reproducibility issues of conventional inorganic setups. The competition between the Coulomb interaction and distortion-induced changes in ligand fields requires methodologies beyond the state-of-the-art: Combining density functional theory with many-body techniques, we demonstrate experimentally feasible tensile strain to trigger a low-spin ($S=1$) to high-spin ($S=2$) crossover. Concomitantly, the current through the device toggles by over an order of magnitude, adding a fully planar mechanical current-switch unit to the panoply of molecular spintronics.

6 pages, 4 figures plus Supporting Information and TOC graphics

References in corpus (11)

• The numerical renormalization group method for quantum impurity systems
• Supramolecular Spin Valves
• Magnetoresistance through a single molecule
• Electric Field Controlled Magnetic Anisotropy in a Single Molecule
• Graphene as a reversible spin manipulator of molecular magnets
• Electrically addressing the spin of a magnetic porphyrin through covalently connected graphene electrodes
• Quantum interference assisted spin filtering in graphene nanoflakes
• Towards a full ab initio theory of strong electronic correlations in nanoscale devices
• Realistic theory of electronic correlations in nanoscopic systems
• Smart local orbitals for efficient calculations within density functional theory and beyond
• Role of charge transfer in hybridization-induced spin transition in metal-organic molecules