"Universal" $Δ_{max}/T_c$ in Fe Based Superconductors

Fuente: arXiv
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Autori principali: Panda, Siddhant, Hirschfeld, P. J.
Natura: Preprint
Pubblicazione: 2023
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author Panda, Siddhant
Hirschfeld, P. J.
author_facet Panda, Siddhant
Hirschfeld, P. J.
contents Iron-based superconductors display a large degree of variability in electronic structure at the Fermi surface, resulting in superconducting gap structures,$T_c$'s, and other properties that vary considerably from family to family. Recently it was noted that across many different families of Fe-based systems, the ratio $Δ_{max}/T_c$ is found to be quasi-universal with a large value of ~3.5 compared to the the one-band BCS weak-coupling result of 1.76. Here $Δ_{max}$ is the measured maximum gap across the Fermi surface. This remarkable fact was attributed to strong-coupling effects arising from Hund's metal physics. Here we perform a "high-throughput" scan across band masses, Fermi energies, and interaction parameters in a weak-coupling Suhl-Matthias-Walker model. We find that unexpectedly large values of $Δ_{max}/T_c$ can be achieved within weak coupling, and that quasiuniversal behavior similar to experiment emerges for those systems where interband interactions dominate intraband ones. However, within the current framework, a large mass contrast between bands is required.
format Preprint
id arxiv_https___arxiv_org_abs_2306_05512
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle "Universal" $Δ_{max}/T_c$ in Fe Based Superconductors
Panda, Siddhant
Hirschfeld, P. J.
Superconductivity
Iron-based superconductors display a large degree of variability in electronic structure at the Fermi surface, resulting in superconducting gap structures,$T_c$'s, and other properties that vary considerably from family to family. Recently it was noted that across many different families of Fe-based systems, the ratio $Δ_{max}/T_c$ is found to be quasi-universal with a large value of ~3.5 compared to the the one-band BCS weak-coupling result of 1.76. Here $Δ_{max}$ is the measured maximum gap across the Fermi surface. This remarkable fact was attributed to strong-coupling effects arising from Hund's metal physics. Here we perform a "high-throughput" scan across band masses, Fermi energies, and interaction parameters in a weak-coupling Suhl-Matthias-Walker model. We find that unexpectedly large values of $Δ_{max}/T_c$ can be achieved within weak coupling, and that quasiuniversal behavior similar to experiment emerges for those systems where interband interactions dominate intraband ones. However, within the current framework, a large mass contrast between bands is required.
title "Universal" $Δ_{max}/T_c$ in Fe Based Superconductors
topic Superconductivity
url https://arxiv.org/abs/2306.05512