Dresden 2014 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 73: Transport: Carbon Nanotubes (organized by TT)

TT 73.6: Talk

Wednesday, April 2, 2014, 17:45–18:00, HSZ 304

Fingerprints of thermal quasiparticle excitations in CNT-superconductor hybrid junctions — •Sebastian Pfaller¹, Andrea Donarini¹, Markus Gaass², Andreas K. Hüttel², Thomas Geiger², Christoph Strunk², and Milena Grifoni¹ — ¹Institute for Theoretical Physics, University of Regensburg, 93040 Regensburg, Germany — ²Institute for Exp. and Applied Physics, University of Regensburg, 93040 Regensburg, Germany

We present a study of a electronic transport through a carbon nanotube quantum dot coupled to superconducting contacts. By increasing the temperature above 300mK additional transport features are observed in the stability diagrams. They appear as lines in the Coulomb blockade region, and are attributed to sequential tunneling of thermally excited quasiparticles. Whenever two of these lines cross at zero bias, a conductance peak is observed. In particular, we observe two of these peaks in the vicinity of the charge degeneracy point. The nature of these lines as well as their temperature dependence can be explained by a transport theory based on a generalized master equation approach to lowest order in the tunnel coupling [1].
S. Pfaller et al. Phys. Rev. B 87, 155439 (2013)