Dresden 2011 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 55: Surface magnetism II (jointly with MA)

O 55.7: Vortrag

Mittwoch, 16. März 2011, 16:30–16:45, CHE 184

Observing the Spin of an Individual Mn₁₂ Molecule — •Steffen Kahle¹, Zhitao Deng¹, Charlène Tonnoir¹, Nicha Thontasen¹, Gordon Rinke¹, Nikola Malinowski¹, Alicia Forment Aliaga¹, Stephan Rauschenbach¹, Markus Ternes¹, and Klaus Kern^1,2 — ¹MPI for Solid State Research, Stuttgart — ²EPFL, Lausanne, Switzerland

The Mn₁₂-acetate₁₆ molecule (Mn₁₂) is considered a prototypical single molecular magnet (SMM) because its high spin measured in bulk is commonly attributed as spin of the individual molecules [1]. To confirm this we want to measure the spin of an individual Mn₁₂ molecule.

We are able to gently deposit Mn₁₂ molecules on different metal substrates by electrospray ion beam deposition [2]. STM images show intact and individual addressable molecules, which can be resolved with submolecular resolution.

Low temperature (1K) scanning tunneling spectroscopy on top of the molecule adsorbed on bare metal is featureless near E_F. This changes when we decouple the molecule from the metal adding a BN layer on the substrate before deposition. We now observe symmetric inelastic tunneling features around E_F in the range of a few mV, which is ascribed to spin flip excitations. The excitation is delocalized evenly over the whole molecule supporting the giant-spin model.

This proofs the existence of a molecular spin, thus confirming the SMM nature of individual Mn₁₂ molecules on the surface.

[1] R. Sessoli et. al., Nature 365, 141, (1993).

[2] N. Thontasen et. al., J. Phys. Chem. C 114, 17768, (2010).