Regensburg 2022 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 3: Superconductivity: Properties and Electronic Structure
TT 3.13: Vortrag
Montag, 5. September 2022, 12:45–13:00, H23
Vortex inductance as a directional probe of Lifshitz invariants in synthetic Rashba-superconductors — Lorenz Fuchs1, Denis Kochan1, Christian Baumgartner1, Simon Reinhardt1, Sergei Gronin2, Geoffrey C. Gardner2, Tyler Lindemann2, Michael J. Manfra2, Christoph Strunk1, and •Nicola Paradiso1 — 1University of Regensburg — 2Purdue University
In type II superconductors, the magnetic field penetrates the sample in quantized units of flux, which correspond to vortices in the superfluid. To save condensation energy, vortices tend to be pinned to defects. If these are sharp, the pinning potential U(r→) is harmonic near the vortex core, where it mirrors the superfluid density |Ψ(r→)|2. In this work, we show that in 2D Rashba superconductors the combination of spin orbit interaction and in-plane magnetic field leads to an anisotropic squeezing of the vortex core. This, in turn, produces a strong enhancement of the pinning strength, which can be measured by vortex inductance measurements. To this end, we developed a technique to measure small inductances which is compatible with the application of both DC bias and strong magnetic fields. Vortex inductance is sensitive to the curvature of the pinning potential along the direction perpendicular to the supercurrent. Thus, our method enables a full tomography of the vortex core, obtained by measuring inductance as a function of the angle between current and field. Our results can be interpreted as the effect of the spin orbit-induced Lifshitz invariant term in the Ginzburg-Landau free energy.