Josephson effect in a fractal geometry

Fuente: arXiv
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Autores principales: Amundsen, Morten, Juričić, Vladimir, Ouassou, Jabir Ali
Formato: Preprint
Publicado: 2024
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author Amundsen, Morten
Juričić, Vladimir
Ouassou, Jabir Ali
author_facet Amundsen, Morten
Juričić, Vladimir
Ouassou, Jabir Ali
contents The Josephson effect is a hallmark signature of the superconducting state, which, however, has been sparsely explored in non-crystalline superconducting materials. Motivated by this, we consider a Josephson junction consisting of two superconductors with a fractal metallic interlayer, which is patterned as a Sierpiński carpet by removing atomic sites in a self-similar and scale-invariant manner. We here show that the fractal geometry has direct observable consequences on the Josephson effect. In particular, we demonstrate that the form of the supercurrent-magnetic field relation as the fractal generation number increases can be directly related to the self-similar fractal geometry of the normal metallic layer. Furthermore, the maxima of the corresponding diffraction pattern directly encode the self-repeating fractal structure in the course of fractal generation, implying that the corresponding magnetic length directly probes the shortest length scale in the given fractal generation. Our results should motivate future experimental efforts to verify these predictions in designer quantum materials and motivate future pursuits regarding fractal-based SQUID devices.
format Preprint
id arxiv_https___arxiv_org_abs_2404_01373
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Josephson effect in a fractal geometry
Amundsen, Morten
Juričić, Vladimir
Ouassou, Jabir Ali
Superconductivity
Mesoscale and Nanoscale Physics
The Josephson effect is a hallmark signature of the superconducting state, which, however, has been sparsely explored in non-crystalline superconducting materials. Motivated by this, we consider a Josephson junction consisting of two superconductors with a fractal metallic interlayer, which is patterned as a Sierpiński carpet by removing atomic sites in a self-similar and scale-invariant manner. We here show that the fractal geometry has direct observable consequences on the Josephson effect. In particular, we demonstrate that the form of the supercurrent-magnetic field relation as the fractal generation number increases can be directly related to the self-similar fractal geometry of the normal metallic layer. Furthermore, the maxima of the corresponding diffraction pattern directly encode the self-repeating fractal structure in the course of fractal generation, implying that the corresponding magnetic length directly probes the shortest length scale in the given fractal generation. Our results should motivate future experimental efforts to verify these predictions in designer quantum materials and motivate future pursuits regarding fractal-based SQUID devices.
title Josephson effect in a fractal geometry
topic Superconductivity
Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2404.01373