Berlin 2024 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 21: Focus Session: Strongly Disordered Superconductors

TT 21.2: Hauptvortrag

Dienstag, 19. März 2024, 10:00–10:30, H 0104

Vortices in dirty superconducting films — •Elio König — Max-Planck Institute for Solid State Research, 70569 Stuttgart, Germany

In this talk about the long standing question of superconductivity in dirty two-dimensional samples I will first review exemplary experiments and summarize theories put forward within the two main paradigms dubbed "bosonic" and "fermionic" approach, respectively.

Next, I will present a theory for the finite temperature vortex-unbinding transition in homogeneously disordered superconducting films. This theory incorporates the effects of quantum, mesoscopic, and thermal fluctuations stemming from length scales ranging from the superconducting coherence length down to the Fermi wavelength and allows to determine the dependence of essential observables on microscopic characteristics.

Finally, the last part of the talk is dedicated to the voltage generation in 2D superconducting films of finite width (strips) at zero temperature and subjected to a finite current bias. We show by means of a variational Ansatz that the voltage is generated by multi-vortex configurations (instead of single or double vortex configurations considered previously). At the border of its applicability, our theory also evidences the superconductor-insulator quantum phase transition.