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TT: Tiefe Temperaturen

TT 14: Symposium Molecular Electronics

TT 14.3: Fachvortrag

Tuesday, March 28, 2006, 10:30–11:00, HSZ 02

Transport through single molecules: vibrational and magnetic excitations — •Maarten Wegewijs, Christian Romeike, Herbert Schoeller, and Walter Hofstetter — Institut fuer theoretische Physik A RWTH-Aachen

We discuss the effects of vibrational and magnetic excitations localized on a molecule on the electron tunneling transport.

In the limit of weak tunnel coupling, we show that a distortion of the vibrational potential shape induced by the charging leads to marked transport signatures. Quantum interference of the mechanical motion of the molecule shows up as a suppression of the transport current. Secondly, we show that quantum-tunneling of the magnetic moment in a single molecular magnet leads to oscillations of the transport current and shot-noise. These molecules exhibit a large ground state spin S and a magnetic anisotropy barrier. The weak quantum tunneling effects do not affect the electron addition spectrum but nevertheless lead to visible non-equilibrium shifts of current and noise resonances.

In the limit of strong tunnel coupling we investigate Kondo-tunneling through single-molecular magnets. We show that the quantum-tunneling of the magnetic moment induces a Kondo effect in the electron transport.