Regensburg 2007 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 8: Superconductivity - Poster Session

TT 8.43: Poster

Montag, 26. März 2007, 14:00–17:45, Poster A

Interaction-Induced Renormalization of Andreev Reflection — •Wolfgang Belzig, Mikhail Titov, and Markus Müller — Department of Physics, University of Konstanz, 78457 Konstanz

Understanding the influence of interaction effects is of fundamental importance in the study of electronic transport through low-dimensional nanostructures. In our work we analyze the charge transport between a one-dimensional weakly interacting electron gas and a superconductor within the scaling approach in the basis of scattering states. We derive and solve the renormalization group equations [1], which fully take into account the intrinsic energy of the scattering matrix due to Andreev reflection. We find a strong renormalization of the Andreev reflection phase even for a prefectly transparent normal metal-superconductor interface. We discuss the effect of this unexpected phase renormalization on the supercurrent through a long superconductor-normal metal-superconductor junction. Our results predict a high sensitivity of the interaction-induced suppression of the Andreev conductance on the normal-state resistance, and thereby provide a possible explanation of experiments with single-walled carbon-nanotube/superconductor junctions [2].
[1] M. Titov, M. Müller, and W. Belzig, Phys. Rev. Lett. 97 237006 (2006).
[2] A. F. Morpurgo, J. Kong, C. M. Marcus, and H. Dai, Science 286, 263 (1999).