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Séminaire de l’axe Matériaux 2D de l’INSP

Addressing spin-crossover molecules on metallic substrate by voltage pulses and light - Amandine Bellec - Mardi 10 septembre 2019 à 11 h

INSP - Sorbonne Université - 4 place Jussieu - 75005 Paris - Barre 22-12, 4e étage, salle 426

Amandine Bellec - Laboratoire Matériaux et Phénomènes Quantiques

Abstract

Spin-crossover molecules show the unique ability to switch between two spin-states by means of external stimuli such as temperature, light or voltage. If controlled at the molecular scale, such switches would be of great interest for the development of molecular devices in electronics and spintronics. If the behavior of such molecules is well documented in bulk, little is known on their properties at the molecular scale and in direct contact with an electrode. We focus our recent studies on FeII pyrazolyl borate molecules (FePz) adsorbed on metallic substrates (Au(111) and Cu(111)). Once absorbed on surfaces, FePz molecules self-assembled in a 2D lattice in which both spin states can coexist at low temperature [1-3] while in bulk only the low spin state is stable. Thanks to scanning tunneling microscopy, we followed at the molecular scale the light transition dynamics of the molecules. Surprisingly, it appears that in direct contact with the metal the molecules are switched from high spin state to a low spin state on the contrary to the bulk behavior. In addition, we demonstrate the possibility to selectively address single molecules in a 2D molecular array.

References

[1] K. Bairagi et al., Nat. Comm. 7, 12212 (2016)
[2] K. Bairagi et al., J. Phys. Chem. C 122, 727 (2018)
[3] C. Fourmental et al., J. Phys. Chem. Lett. 10, 4103 (2019)