Berlin 2015 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 54: Superconductivity: Heterostructures

TT 54.2: Vortrag

Mittwoch, 18. März 2015, 10:00–10:15, H 3005

On the universality of the "smile"-gap in the Density of States of a chaotic Josephson junction — •Johannes Reutlinger¹, Yuli Nazarov², Leonid Glazman³, and Wolfgang Belzig¹ — ¹University of Konstanz, Department of Physics, 78457 Konstanz, Germany — ²Kavli Institute of Nanoscience Delft, Delft University of Technology, 2628 CJ Delft, Netherlands — ³Department of Physics, Yale University, New Haven CT 06511-8499, USA

The superconducting proximity effect strongly modifies the local density of states in chaotic Josephson junctions. Recently we found that besides the well-known minigap a secondary gap appears just below the superconducting gap edge Δ in the limit of a large Thouless energy E_ThΔ 1 . To check the universality of this novel gap phenomenon we study the effect of nonideal contacts and show that the "smile"-gap crucially depends on the transmission eigenvalue distribution 2 . In a next step we use the random matrix method to investigate the "smile"-gap. This allows us to approach the statistics of Andreev levels, going beyond the quasiclassical Greens function method. It turns out that the hard gap edge softens similar to what is already known from the minigap.

1 J. Reutlinger, L. Glazman, Yu. V. Nazarov, W. Belzig,

Phys. Rev. Lett. 112, 067001 (2014)

2 J. Reutlinger, L. Glazman, Yu. V. Nazarov, W. Belzig,

Phys. Rev. B 90, 014521 (2014)