Anisotropic, multiband, and strong-coupling superconductivity of the Pb0.64Bi0.36 alloy

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Hauptverfasser: Gutowska, Sylwia, Górnicka, Karolina, Wójcik, Paweł, Klimczuk, Tomasz, Wiendlocha, Bartlomiej
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Veröffentlicht: 2024
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author Gutowska, Sylwia
Górnicka, Karolina
Wójcik, Paweł
Klimczuk, Tomasz
Wiendlocha, Bartlomiej
author_facet Gutowska, Sylwia
Górnicka, Karolina
Wójcik, Paweł
Klimczuk, Tomasz
Wiendlocha, Bartlomiej
contents This paper presents theoretical and experimental studies on the superconductivity of Pb${_{0.64}}$Bi$_{0.36}$ alloy, which is a prototype of strongly coupled superconductors and exhibits one of the strongest coupling under ambient pressure among the materials studied so far. The critical temperature, the specific heat in the superconducting state, and the magnetic critical fields are experimentally determined. Deviations from the single-gap s-wave BCS-like behavior are observed. The electronic structure, phonons and electron-phonon interactions are analyzed in relation to the metallic Pb, explaining why the Pb-Bi alloy exhibits such a large value of the electron-phonon coupling parameter $λ\simeq 2$. Superconductivity is studied using the isotropic Eliashberg formalism as well as the anisotropic density functional theory for superconductors. We find that while Pb is a two-gap superconductor with well-defined separate superconducting gaps, in the Pb-Bi alloy an overlapped three-gap-like structure is formed with a strong anisotropy. Furthermore, the chemical disorder, inherent to this alloy, leads to strong electron scattering, which is found to reduce the critical temperature.
format Preprint
id arxiv_https___arxiv_org_abs_2411_18315
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Anisotropic, multiband, and strong-coupling superconductivity of the Pb0.64Bi0.36 alloy
Gutowska, Sylwia
Górnicka, Karolina
Wójcik, Paweł
Klimczuk, Tomasz
Wiendlocha, Bartlomiej
Superconductivity
Materials Science
This paper presents theoretical and experimental studies on the superconductivity of Pb${_{0.64}}$Bi$_{0.36}$ alloy, which is a prototype of strongly coupled superconductors and exhibits one of the strongest coupling under ambient pressure among the materials studied so far. The critical temperature, the specific heat in the superconducting state, and the magnetic critical fields are experimentally determined. Deviations from the single-gap s-wave BCS-like behavior are observed. The electronic structure, phonons and electron-phonon interactions are analyzed in relation to the metallic Pb, explaining why the Pb-Bi alloy exhibits such a large value of the electron-phonon coupling parameter $λ\simeq 2$. Superconductivity is studied using the isotropic Eliashberg formalism as well as the anisotropic density functional theory for superconductors. We find that while Pb is a two-gap superconductor with well-defined separate superconducting gaps, in the Pb-Bi alloy an overlapped three-gap-like structure is formed with a strong anisotropy. Furthermore, the chemical disorder, inherent to this alloy, leads to strong electron scattering, which is found to reduce the critical temperature.
title Anisotropic, multiband, and strong-coupling superconductivity of the Pb0.64Bi0.36 alloy
topic Superconductivity
Materials Science
url https://arxiv.org/abs/2411.18315