CINaM - Centre Interdisciplinaire de Nanoscience de Marseille


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jeudi 22 Mars 2018 à 14H00
CINaM - Salle Raymond Kern
Mickaël Kepenekian
Institut des Sciences Chimiques de Rennes (ISCR), CNRS - Université de Rennes 1
Towards highly cooperative spin-crossover metal-organic frameworks on metallic surfaces

The design of molecular-based devices to manipulate spin has driven many investigations opening the field of molecular spintronics [1]. In this context, molecular bistability has drawn much attention and the most promising objects arise from molecular magnetism. Although recent realizations have been achieved with single molecules, such setups disrupt the required inter-site cooperativity that turns a slowly commuting system into a rapidly switching set of molecules. An auspicious path comes from the use of metal-organic frameworks (MOF) self-assembled on surfaces, which offer the opportunity to tailor interactions between magnetic sites.

Based on density functional theory, we first elucidate the structure, electronic structure and magnetic properties of a recently proposed Fe-based MOF self-assembled on the Au(111) surface [2]. We then propose a chemical strategy to turn a weakly interacting magnetic system into a strongly cooperative spin-crossover monolayer. Finally using a thermodynamic model, we demonstrate how the dimensionality reduction combined to deposition on a metal surface enhance the electrostatic contributions to spin-crossover cooperativity, going from Γ3D = 16 K for the bulk material to Γ2Dsupp = 386 K for its 2D supported derivative [3]. With the ability to enhance cooperativity in a rational way, a promising route is opened towards the design of molecular spintronic devices.

References [1] L. Bogani, W. Wernsdorfer, Nature Mater. 7, 179 (2008). S. Sanvito, Chem. Soc. Rev. 40, 3336 (2011). S. V. Aradhya, L. Venkataraman, Nature Nanotech. 8, 399 (2013).

[2] T. R. Umbach, M. Bernien, C. F. Hermanns, A. Krüger, V. Sessi, I. Fernandez-Torrente, P. Stoll, J. I. Pascual, K. J. Franke, W. Kuch, Phys. Rev. Lett. 109, 267207 (2012).

[3] T. Groizard, N. Papior, B. Le Guennic, V. Robert, M. Kepenekian, J. Phys. Chem. Lett. 8, 3415 (2017).

Invitation : Laurence Masson - Entrée libre