Naslov
Quantum-critical region of the disorder-driven superconductor – insulator transition

Autori
Baturina, Tatyana ; Bilušić, Ante ; Mironov, Aleksey ; Vinokur, Valerii ; Baklanov, Mikhail ; Strunk, Christoph

Izvornik
Physica. C, Superconductivity (0921-4534) 468 (2008), 4; 316-321

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
superconductivity; socalization; quantum phase transition

Sažetak
We investigate low temperature transport properties of thin TiN superconducting films, differing by the degree of disorder. At zero magnetic field we find an extremely sharp separation between the superconducting- and insulating phases, indicating a direct superconductor– insulator transition without an intermediate metallic phase. We show that in the critical region of the transition a peculiar highly inhomogeneous insulating state with superconducting correlations forms. The insulating films exhibit thermally activated conductivity and huge positive magnetoresistance at low magnetic fields. A sharp depinning transition at some voltage VT is observed in the I– V curves at very low temperatures. We propose a percolation type of depinning with the threshold voltage determined by the Coulomb blockade energy for the Cooper pairs between neighboring self-induced superconducting islands, with VT being the total voltage along the first conduction path. The observed hysteretic behavior of the threshold and steps on the dI/dV vs. V curves support this percolation picture of the depinning transition.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

Napomena
Rad je prezentiran na skupu Tthe Workshop on Fluctuations and Phase Transitions in Superconductors, održanom od 10.–14.06.2007., Nazareth Ilit, Israel.

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