Can the noble metals (Au, Ag and Cu) be superconductors?

Fuente: arXiv
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Main Authors: Ummarino, Giovanni A., Zaccone, Alessio
Format: Preprint
Published: 2024
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author Ummarino, Giovanni A.
Zaccone, Alessio
author_facet Ummarino, Giovanni A.
Zaccone, Alessio
contents It is common knowledge that noble metals are excellent conductors but do not exhibit superconductivity. On the other hand, quantum confinement in thin films has been consistently shown to induce a significant enhancement of the superconducting critical temperature in several superconductors. It is therefore an important fundamental question whether ultra-thin film confinement may induce observable superconductivity in non-superconducting metals. We present a generalization, in the Eliashberg framework, of a BCS theory of superconductivity in good metals under thin-film confinement. By numerically solving these new Eliashberg-type equations, we find the dependence of the superconducting critical temperature on the film thickness $L$. This parameter-free theory predicts a maximum increase in the critical temperature for a specific value of the film thickness, which is a function of the number of free carriers in the material. Exploiting this fact, we predict that ultra-thin films of gold, silver and copper of suitable thickness could be superconductors at low but experimentally accessible temperatures. We demonstrate that this is a fine-tuning problem where the thickness must assume a very precise value, close to half a nanometer.
format Preprint
id arxiv_https___arxiv_org_abs_2406_16621
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Can the noble metals (Au, Ag and Cu) be superconductors?
Ummarino, Giovanni A.
Zaccone, Alessio
Superconductivity
Mesoscale and Nanoscale Physics
Materials Science
Strongly Correlated Electrons
Quantum Physics
It is common knowledge that noble metals are excellent conductors but do not exhibit superconductivity. On the other hand, quantum confinement in thin films has been consistently shown to induce a significant enhancement of the superconducting critical temperature in several superconductors. It is therefore an important fundamental question whether ultra-thin film confinement may induce observable superconductivity in non-superconducting metals. We present a generalization, in the Eliashberg framework, of a BCS theory of superconductivity in good metals under thin-film confinement. By numerically solving these new Eliashberg-type equations, we find the dependence of the superconducting critical temperature on the film thickness $L$. This parameter-free theory predicts a maximum increase in the critical temperature for a specific value of the film thickness, which is a function of the number of free carriers in the material. Exploiting this fact, we predict that ultra-thin films of gold, silver and copper of suitable thickness could be superconductors at low but experimentally accessible temperatures. We demonstrate that this is a fine-tuning problem where the thickness must assume a very precise value, close to half a nanometer.
title Can the noble metals (Au, Ag and Cu) be superconductors?
topic Superconductivity
Mesoscale and Nanoscale Physics
Materials Science
Strongly Correlated Electrons
Quantum Physics
url https://arxiv.org/abs/2406.16621