Dresden 2011 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 21: TR: Nanoelectronics III - Molecular Electronics 2

TT 21.9: Talk

Tuesday, March 15, 2011, 12:45–13:00, HSZ 301

Vibration-assisted tunneling through a molecular level with competing phonon modes — •Federica Haupt^1,2, Johannes Buelte¹, and Wolfgang Belzig¹ — ¹Fachbereich Physik, Universität Konstanz, D-78457 Konstanz, Germany — ²Institut für Theoretische Physik A, RWTH Aachen, D-52074 Aachen, Germany

We investigate the electronic transport properties of a single electronic level weakly coupled to leads and interacting with two different phonon modes. We consider the interplay between the two phonon modes under the assumption that tunneling induces a non–equilibrium vibrational distribution and compare to the opposite limit of strong relaxation of the vibrations due to some dissipative environment. We show that in the presence of non–equilibrium the tunneling electrons mediate an effective interaction between the two phonon modes. This results in characteristic features in the transport properties of the device such as sub-threshold excitation of one phonon mode and the appearance of negative differential conductance in a wide range of parameters.