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PGI Kolloquium:

Prof. Dr. Nacho Pascual,
Nanoimaging Group, CIC nanoGUNE, San Sebastian, Spain

PGI Lecture Hall, Building 04.8, 2nd Floor, Room 365

28.11.2014 11:00 Uhr

Exciting Spin, Forces and Photons in Molecular Tunneling Junctions

We use a scanning tunneling microscope (STM) at cryogenic conditions as a tool to investigate the effects of electronic currents on individual molecules adsorbed on a metal surface.

I will present recent results on spin excitations, molecular conformational transformations, or vibrational heating induced by electrons.

I) We induce spin excitations in paramagnetic molecules on a superconducting substrate. An interesting outcome is that the lifetime of excited states amounts to a few nanoseconds, much larger than on normal metal surfaces. II) Molecular conformational changes can be induced by inelastic tunneling electrons. We identify these conformational changes through the forces exerted on the tip of an STM. III) Tunneling electrons through molecular junctions can also induce light emission. The spectroscopic characterization of emitted photons reveals “anti-stokes”-like phenomena, which we interpret as induced by hot molecular modes, excited by inelastic tunneling electrons.


Prof. Dr. Maarten Rolf Wegewijs
Telefon: +49 2461 61-4017
Fax: +49 2461 61-2620