Isotropically gapped strong-coupling superconductivity in the beta-pyrochlore KOs2O6: evidence from penetration depth measurements.
Bonalde. I I; Ribeiro. R R; Brämer-Escamilla. W W; Yamaura. J J; Nagao. Y Y; Hiroi. Z Z
Key Findings
- Isotropic superconducting gap observed below ~0.3 Tc
- Strong‑coupling BCS model fits the superfluid density
- Second phase transition at 7.5 K does not affect penetration depth
Practical Outcomes
- There are no practical takeaways for biohackers or anyone looking to use selank; the findings are purely physics‑focused and not applicable to health protocols.
Summary
The paper studies a crystal called KOs2O6 and shows it becomes a strong‑coupling superconductor with an isotropic energy gap, but it has nothing to do with the peptide selank or human health.
Abstract
We report on measurements of the temperature dependence of the magnetic penetration depth down to 0.04 K in a high-quality sample of the beta-pyrochlore KOs2O6 (Tc=9.65 K) with a spin-frustrated lattice. We observe temperature-independent behavior below T approximately 0.3Tc, which is firm evidence for the presence of an isotropic superconducting gap in this material. In the whole temperature range the superfluid density is very well described, without the need of adjustable parameters, by a strong-coupling extension of the BCS model for an isotropic gap. Thus, the penetration depth results indicate that KOs2O6 is a strong-coupling superconductor with a fully developed energy gap. No effect of the second phase transition taking place at Tp=7.5 K was observed on the penetration depth, which suggests that the Cooper pairs remain unperturbed across this transition.
Study Information
pubmed
2007
2007-06-01T00:00:00.000Z
10.1103/physrevlett.98.227003