Year: 2024
Type: article
Abstract: The pressure dependence of the thermodynamic critical field B c in elemental indium (In) and tin (Sn) superconductors was studied by means of muon-spin rotation/relaxation. Pressure enhances the deviation of B c ( T ) from the parabolic behavior expected for a typical type-I superconductor, suggesting a weakening of the coupling strength α = 〈 Δ 〉 / k B T c ( 〈 Δ 〉 is the average value of the superconducting energy gap, T c is the transition temperature, and k B is the Boltzmann constant). As pressure increases from 0.0 to ≃ 3.0 GPa, α decreases linearly, approaching the limiting weak-coupling Bardeen-Cooper-Schrieffer (BCS) value α BCS ≃ 1.764 . Analysis of the data within the framework of Eliashberg theory reveals that only part of the pressure effect on α can be attributed to the hardening of the phonon spectra, reflected by a decrease in the electron-phonon coupling constant. Nearly 40% of the effect is caused by an increased anisotropy of the superconducting energy gap. Published by the American Physical Society 2024
Authors: Rustem Khasanov, Giovanni A. Ummarino
Language: English
Subfield: Condensed Matter Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: hybrid
Funder: Paul Scherrer Institut
OpenAlex ID: W4405639005