Stroboscopic phenomena in superconductors with dynamic pinning landscape.

Ž L Jelić,M V Milošević,A V Silhanek,J Van De Vondel

doi:10.1038/srep14604

Ž L Jelić, M V Milošević + Show 2 more

Open Access

https://doi.org/10.1038/srep14604

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Abstract

Introducing artificial pinning centers is a well established strategy to trap quantum vortices and increase the maximal magnetic field and applied electric current that a superconductor can sustain without dissipation. In case of spatially periodic pinning, a clear enhancement of the superconducting critical current arises when commensurability between the vortex configurations and the pinning landscape occurs. With recent achievements in (ultrafast) optics and nanoengineered plasmonics it has become possible to exploit the interaction of light with superconductivity, and create not only spatially periodic imprints on the superconducting condensate, but also temporally periodic ones. Here we show that in the latter case, temporal matching phenomena develop, caused by stroboscopic commensurability between the characteristic frequency of the vortex motion under applied current and the frequency of the dynamic pinning. The matching resonances persist in a broad parameter space, including magnetic field, driving current, or material purity, giving rise to unusual features such as externally variable resistance/impedance and Shapiro steps in current-voltage characteristics. All features are tunable by the frequency of the dynamic pinning landscape. These findings open further exploration avenues for using flashing, spatially engineered, and/or mobile excitations on superconductors, permitting us to achieve advanced functionalities.

Highlights

Would a dynamic pinning landscape affect the superconducting properties? Clearly, the added degrees of freedom in terms of frequency and strength of the pinning, as well as its possible mobility and speed, next to its spatial geometry, could trigger new phenomena unattainable with static pinning
Light as a source of a time-dependent pinning potential in superconductors has not been explored to date, it has been utilized for dynamic optical scanning in Bose-Einstein condensates (BECs)[24], and for flashing ratchets in colloidal systems[25,26,27,28,29,30,31]
What phenomenology should one expect from the frequency dependence of the pinning landscape? Clearly, if the change between the ON and OFF state of the pinning potential is faster than the characteristic relaxation time of the superconducting order parameter (i.e. τ τGL, where τGL is the Ginzburg-Landau relaxation time, see Methods), a recovery of the superconducting condensate is not possible—leading to permanent depletion and effectively static pinning

Summary

Introduction

Would a dynamic pinning landscape affect the superconducting properties? Clearly, the added degrees of freedom in terms of frequency and strength of the pinning, as well as its possible mobility and speed, next to its spatial geometry, could trigger new phenomena unattainable with static pinning.

Results

Conclusion