English

$H_{3}S$ is a high-$\kappa$ superconductor with columnar pinning defects

Superconductivity 2023-02-13 v2 Strongly Correlated Electrons

Abstract

Recently, the existence of superconductivity in H3S\mathrm{H_{3}S} and other high-pressure hydrides is called into question, because of some flawed magnetic measurements. In Ref.[1] the SCPC model is proposed, where strong pinning of vortices is due to long columnar defects in H3S\mathrm{H_{3}S} - with lengths L\mathrm{L} of the order of vortex lengths Lv\mathrm{L_{v}}. Two relevant type of experiments in magnetic fields are explained by this model: (1) Reduction (with respect to standard superconductors) of the thermal broadening of resistance (TBR\mathit{TBR}) in magnetic field h=H/Hc2\mathrm{h=H/H_{c2}}, δtc(h)\mathrm{\mathrm{\delta t_{c}(h)}}, is governed by the small parameter C=\mathrm{C=}ξ0/L\mathrm{\xi_{0}}/\mathrm{L}. The TBR\mathit{TBR} measurements give, that in H3S\mathrm{H_{3}S} there is a large shift of the irreversible line Birr(T)\mathrm{B_{irr}(T)} towards the Bc2(T)\mathrm{B_{c2}(T)} line. (2) In ZFC (zero field cooled) experiments on penetration of the magnetic field (PMF\mathit{PMF}) in H3S\mathrm{H_{3}S} [3], the latter reaches the center of a superconducting disk at much larger external fields, i. e. for B0Bc1\mathrm{B_{0}\gg B_{c1}}. The later is due to the pronounced pinning of vortices, but not to the Meissner effect. The calculated T\mathrm{T}- dependence of the penetrated, perpendicular B(T)\mathrm{B_{\perp}(T)} and parallel B(T)\mathrm{B_{\parallel}}(\mathrm{T}), magnetic field into the sample is in satisfactory agreement with the experimental results for H3S\mathrm{H_{3}S} in [3], where B>B\mathrm{B_{\perp}>B_{\parallel}}. Problems related to measurements of the Meissner effect in H3S\mathrm{H_{3}S} are also discussed. The SCPC model, applied on the bulk H3S\mathrm{H_{3}S} sample, predicts, that the latter is a high-κ\kappa superconductor.

Keywords

Cite

@article{arxiv.2301.13153,
  title  = {$H_{3}S$ is a high-$\kappa$ superconductor with columnar pinning defects},
  author = {Miodrag L. Kulić},
  journal= {arXiv preprint arXiv:2301.13153},
  year   = {2023}
}

Comments

12 pages, 7 figures. Typos corrected, on p.10 "$\lambda_{0}$ too large" is replaced by "$\lambda_{0}$ too small"