Regensburg 2010 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 33: TR: Nanoelectronics I: Quantum Dots, Wires, Point Contacts 2

TT 33.3: Talk

Thursday, March 25, 2010, 14:30–14:45, H19

Vibration-assisted transport properties of suspended carbon nanotube quantum dots. — •Abdullah Yar, Andrea Donarini, Sonja Koller, and Milena Grifoni — Institut für Theoretische Physik, Universität Regensburg, D-93040 Regensburg,Germany

We investigate the transport properties of suspended armchair single-wall carbon nanotubes (SWNTs) weakly coupled to leads. In the low energy regime, such nano-electromechanical systems behave as quantum dot systems being highly sensitive to the influence of few vibrational modes. We performed a microscopic analysis of suspended metallic SWNTs and included Coulomb interaction effects beyond mean-field, by using bosonization techniques, yielding the spectrum and eigenfunctions of the isolated finite length SWNT. The theory predicts that strong electron-vibron coupling strongly suppresses the current flow at low biases, a collective behavior known as Franck-Condon blockade, in spite of the symmetric coupling to the leads. At larger values of the bias voltage interference between degenerate states can yield a characteristic current suppression.