Vortex Quantum Nucleation and Tunneling in Superconducting Thin Films: Role of Dissipation and Periodic Pinning
| Autor: | R. Iengo, G. Jug |
|---|---|
| Rok vydání: | 1996 |
| Předmět: |
Superconductivity
Materials science Flux pinning Condensed matter physics Condensed Matter - Superconductivity Supercurrent Nucleation General Physics and Astronomy Thermal fluctuations FOS: Physical sciences Vortex Superconductivity (cond-mat.supr-con) Condensed Matter::Superconductivity Quantum dissipation Quantum tunnelling |
| DOI: | 10.48550/arxiv.cond-mat/9611112 |
| Popis: | We investigate the phenomenon of decay of a supercurrent in a superconducting thin film in the absence of an applied magnetic field. The resulting zero-temperature resistance derives from two equally possible mechanisms: 1) quantum tunneling of vortices from the edges of the sample; and 2) homogeneous quantum nucleation of vortex-antivortex pairs in the bulk of the sample, arising from the instability of the Magnus field's ``vacuum''. We study both situations in the case where quantum dissipation dominates over the inertia of the vortices. We find that the vortex tunneling and nucleation rates have a very rapid dependence on the current density driven through the sample. Accordingly, whilst normally the superconductor is essentially resistance-free, for the high current densities that can be reached in high-$T_c$ films a measurable resistance might develop. We show that edge-tunneling appears favoured, but the presence of pinning centres and of thermal fluctuations leads to an enhancement of the nucleation rates. In the case where a periodic pinning potential is artificially introduced in the sample, we show that current-oscillations will develop indicating an effect specific to the nucleation mechanism where the vortex pair-production rate, thus the resistance, becomes sensitive to the corrugation of the pinning substrate. In all situations, we give estimates for the observability of the studied phenomena. Comment: 8 pages (LaTeX), 2 postscript figures. Invited talk to the SATT8 (8th Italian Meeting on High-T_c Superconductivity), Como (Italy), Villa Olmo, 1-4 October 1996, to be published in La Rivista del Nuovo Cimento D |
| Databáze: | OpenAIRE |
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