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Garst, Mirlin, Rockstuhl, Schmalian, Shnirman

Montag, 14.00-15.30 Uhr

10-01

Garst, Rockstuhl

Dienstag, 13.00-14.00 Uhr

10-01

Campus Nord, Geb. 425

Freitag, 15.45-17.15 Uhr

Lehmann HS

Superconductor-Insulator Transition in disordered Josephson junction chains

TKM Institutsseminar

Vortragender:

Matthias Bard

Datum:

04.05.2017 12:30

Ort:

Room 10.01, 10th Floor, Bldg. 30.23, KIT Campus South

Zugehörigkeit:

Karlsruhe Institute of Technology

Gastgeber:

Prof. Dr. Alexander Mirlin

Abstract

We study the superconductor-insulator quantum phase transition in disordered Josephson junction chains. To this end, we derive the field theory from the lattice model that describes a chain of superconducting islands with a capacitive coupling to the ground (C_0) as well as between the islands (C_1). We analyze the theory in the short-range (C_1 << C_0) and in the long-range (C_1 >> C_0) limits. The transition to the insulating state is driven by the proliferation of quantum phase slips. The most important source of disorder originates from trapped charges in the substrate that suppress the coherence of phase slips, thus favoring superconducting correlations. Using the renormalization-group approach, we determine the phase diagram and evaluate the temperature dependence of the dc conductivity and system-size dependence of the resistance around the superconductor-insulator transition. These dependences have in general strongly non-monotonic character, with several distinct regimes reflecting an intricate interplay of superconductivity and disorder.