Pressure weakens coupling strength in In and Sn elemental superconductors
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arXiv
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| Format: | Preprint |
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2024
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| _version_ | 1866915130336346112 |
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| author | Khasanov, Rustem Ummarino, Giovanni A. |
| author_facet | Khasanov, Rustem Ummarino, Giovanni A. |
| contents | Pressure dependence of the thermodynamic critical field $B_{\rm c}$ in elemental indium (In) and tin (Sn) superconductors was studied by means of the muon-spin rotation/relaxation. Pressure enhances the deviation of $B_{\rm c}(T)$ from the parabolic behavior, expected for a typical type-I superconductor, suggesting a weakening of the coupling strengths $α=\langleΔ\rangle /k_{\rm B}T_{\rm c}$ ($\langleΔ\rangle$ is the average value of the superconducting energy gap, $T_{\rm c}$ is the transition temperature and $k_{\rm B}$ is the Boltzmann constant). As pressure increases from 0.0 to $\simeq 3.0$ GPa $α$ decreases linearly, by approaching the limiting weak-coupling BCS value $α_{\rm BCS}=1.764$. Analysis of the data within the framework of the Eliashberg theory reveals that only part of the pressure effect on $α$ can be attributed to the effect of hardening of the phonon spectra, which is reflected by a decrease of the electron-phonon coupling constant. Nearly 40% of the effect is caused by increased anisotropy of the superconducting energy gap. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2408_13857 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Pressure weakens coupling strength in In and Sn elemental superconductors Khasanov, Rustem Ummarino, Giovanni A. Superconductivity Pressure dependence of the thermodynamic critical field $B_{\rm c}$ in elemental indium (In) and tin (Sn) superconductors was studied by means of the muon-spin rotation/relaxation. Pressure enhances the deviation of $B_{\rm c}(T)$ from the parabolic behavior, expected for a typical type-I superconductor, suggesting a weakening of the coupling strengths $α=\langleΔ\rangle /k_{\rm B}T_{\rm c}$ ($\langleΔ\rangle$ is the average value of the superconducting energy gap, $T_{\rm c}$ is the transition temperature and $k_{\rm B}$ is the Boltzmann constant). As pressure increases from 0.0 to $\simeq 3.0$ GPa $α$ decreases linearly, by approaching the limiting weak-coupling BCS value $α_{\rm BCS}=1.764$. Analysis of the data within the framework of the Eliashberg theory reveals that only part of the pressure effect on $α$ can be attributed to the effect of hardening of the phonon spectra, which is reflected by a decrease of the electron-phonon coupling constant. Nearly 40% of the effect is caused by increased anisotropy of the superconducting energy gap. |
| title | Pressure weakens coupling strength in In and Sn elemental superconductors |
| topic | Superconductivity |
| url | https://arxiv.org/abs/2408.13857 |