Design einer Rechenplattform und Untersuchung der Supraleitung in neuartigen aufgerollten Nanostrukturen
Zusammenfassung der Projektergebnisse
Topological defects such as vortices and phase slips in a superconductor system manifest spatial patterns and dynamics that are closely associated with the geometric design in curved microand nanostructures of superconductors. Our study is motivated by the recent progress in fabrication of complex 3D nanoarchitectures (e.g., open nanotubes and nanohelices) by using the advanced 3D roll-up self-organization and nanowriting techniques based on focused ion beams. The emerging nanostructures lead to the occurrence of novel, counterintuitive materials properties of superconductors and thereby promise a significant improvement of the figures-ofmerit as compared to the available devices, for instance, helical bolometers with extremely low Noise Equivalent Power. To simulate, analyze and optimize the superconducting properties of complex high-tech nanoarchitectures, a dedicated numerical platform has been developed on the basis of the Finite Difference Time Domain approach for a set consisting of the timedependent Ginzburg-Landau equation coupled with the Poisson equation and the Maxwell equation. Using this calculation platform, we have gained a new knowledge about physical properties of high-tech superconductor nanostructures, like the behavior of vortex matter in nanoarchitectures of finite thickness with account for renormalization of the magnetic field. Fingerprints of vortex and phase-slip patterns experimentally identified in the nanohelices are explained by the helical geometry that determines a specific topology of screening superconducting currents and paves the way for future electronic components, such as sensors, energy storage elements and nanoantennas, based on 3D compact nanosuperconductors. The topological transitions between vortex-chain and phase-slip transport regimes unveiled in curved superconductor nanostructures as a function of the applied magnetic field under a strong transport current open up a possibility to efficiently tailor the superconducting properties of nanostructured materials by inducing a nontrivial topology of superconductor screening currents. In particular, the non-monotonous magnetic-field-voltage and current-voltage characteristics are found in open rolled-up Nb and Sn microtubes under a strong transport current. This non-monotonous behavior is attributed to the occurrence of a phase-slip area at such magnetic fields, when the quasi-stationary pattern of vortices changes from single to double chains in each half-turn, followed by reentrance of the superconducting state with a chain of moving vortices when the magnetic field further increases. A three-fold induced voltage pulse occurs in an ultrathin open Nb tube of radius 400 nm at the magnetic field about 10 mT. The effect is promising for application design of novel superconductor switching-based detectors. A “surprise” of the present project is a discovery of a phase transition between the vortex-chain and phase-slip regimes in superconducting membranes in a strongly inhomogeneous magnetic field (e.g., in open nanotubes) when we significantly increase the transport current to values approaching the critical current.
Projektbezogene Publikationen (Auswahl)
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“Three-Dimensional Superconducting Nanohelices Grown by He+-Focused-Ion-Beam Direct Writing”, Nano Lett. 19, 8597-8604 (2019)
R. Córdoba, D. Mailly, R. O. Rezaev, E. I. Smirnova, O. G. Schmidt, V. M. Fomin, U. Zeitler, I. Guillamón, H. Suderow, J. M. De Teresa
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“Voltage Induced By Superconducting Vortices In Open Nanostructured Microtubes”, Phys. Stat. Sol. – Rapid Research Letters 13, 1800251, 1-4 (2019)
R. O. Rezaev, E. A. Posenitskiy, E. I. Smirnova, E. A. Levchenko, O. G. Schmidt, and V. M. Fomin
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“Simulation of dynamics of the order parameter in superconducting nanostructured materials: Effect of the magnetic field renormalization”, Low Temperature Physics 46, 395-401 (2020)
E. I. Smirnova, R. O. Rezaev, V. M. Fomin
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“Topological transitions in superconductor nanomembranes in a magnetic field with submicron inhomogeneity under a strong transport current”, Communications Physics 3, 144, 1-7 (2020)
R.O. Rezaev, E.I. Smirnova, O.G. Schmidt, V.M. Fomin
