Regensburg 2016 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 5: Transport: Quantum Coherence and Quantum Information Systems - Experiment
(Joint session of HL, MA and TT organized by TT)
TT 5.11: Talk
Monday, March 7, 2016, 12:45–13:00, H22
Localized quantum phase slips in TiN nanowires — •Ina Schneider1, Tatyana Baturina1,2, and Christoph Strunk1 — 1Inst. f. Exp. und Angewandte Physik, Uni Regensburg — 2Inst. f. Semiconductor Physics, RAS, Novosibirsk, Russia
We investigate TiN nanowires with 780 nm length and widths ranging from 50-780 nm close to the superconductor/insulator transition. In zero magnetic field the superconducting transition of wider wires resembles that of macroscopic films, while narrower wires develop a finite and T-independent resistance down to the lowest temperatures. In perpendicular magnetic field B a pronounced nonmontonic magnetoresistance occurs. The R(T)-curves at fixed B show a reentrant insulating behavior very similar to that of Coulomb-blockaded linear arrays of Josephson junctions [1].
The I(V)-characteristics display a characteristic cross-over from the dc-Josephson effect towards Coulomb blockade at very low voltages and temperatures within a globally superconductive-like I(V). In the linear regime, the magnetoresistance displays strong fluctuations. We interpret our results in terms of disordered Josephson networks with a B-dependent Josephson coupling energy that favors coherent quantum phase slips at certain B.
A. Ergül, et al., NJP 15, 095014 (2014).