Strong enhancement of superconductivity on finitely ramified fractal lattices

Fuente: arXiv
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Hauptverfasser: Iliasov, Askar A., Canyellas, Robert, Katsnelson, Mikhail I., Bagrov, Andrey A.
Format: Preprint
Veröffentlicht: 2023
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author Iliasov, Askar A.
Canyellas, Robert
Katsnelson, Mikhail I.
Bagrov, Andrey A.
author_facet Iliasov, Askar A.
Canyellas, Robert
Katsnelson, Mikhail I.
Bagrov, Andrey A.
contents Using the Sierpinski gasket (triangle) and carpet (square) lattices as examples, we theoretically study the properties of fractal superconductors. For that, we focus on the phenomenon of $s$-wave superconductivity in the Hubbard model with attractive on-site potential and employ the Bogoliubov-de Gennes approach and the theory of superfluid stiffness. For the case of the Sierpinski gasket, we demonstrate that fractal geometry of the underlying crystalline lattice can be strongly beneficial for superconductivity, not only leading to a considerable increase of the critical temperature $T_c$ as compared to the regular triangular lattice but also supporting macroscopic phase coherence of the Cooper pairs. In contrast, the Sierpinski carpet geometry does not lead to pronounced effects, and we find no substantial difference as compared with the regular square lattice. We conjecture that the qualitative difference between these cases is caused by different ramification properties of the fractals.
format Preprint
id arxiv_https___arxiv_org_abs_2310_11497
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Strong enhancement of superconductivity on finitely ramified fractal lattices
Iliasov, Askar A.
Canyellas, Robert
Katsnelson, Mikhail I.
Bagrov, Andrey A.
Superconductivity
Strongly Correlated Electrons
Quantum Physics
Using the Sierpinski gasket (triangle) and carpet (square) lattices as examples, we theoretically study the properties of fractal superconductors. For that, we focus on the phenomenon of $s$-wave superconductivity in the Hubbard model with attractive on-site potential and employ the Bogoliubov-de Gennes approach and the theory of superfluid stiffness. For the case of the Sierpinski gasket, we demonstrate that fractal geometry of the underlying crystalline lattice can be strongly beneficial for superconductivity, not only leading to a considerable increase of the critical temperature $T_c$ as compared to the regular triangular lattice but also supporting macroscopic phase coherence of the Cooper pairs. In contrast, the Sierpinski carpet geometry does not lead to pronounced effects, and we find no substantial difference as compared with the regular square lattice. We conjecture that the qualitative difference between these cases is caused by different ramification properties of the fractals.
title Strong enhancement of superconductivity on finitely ramified fractal lattices
topic Superconductivity
Strongly Correlated Electrons
Quantum Physics
url https://arxiv.org/abs/2310.11497