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Published on: August 2, 2019
Evidence for fully gapped strong coupling s-wave superconductivity in Bi4O4S3
Shruti1, P Srivastava, S Patnaik
1School of Physical Sciences, Jawaharlal Nehru University, New Delhi-110067, India.
Summary
This study reveals Bi4O4S3 as a conventional s-wave superconductor. Its superconducting energy gap is significantly larger than predicted by BCS theory, indicating strong coupling.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Superconductivity
Background:
- Layered superconductors offer unique electronic properties.
- Understanding pairing symmetry is crucial for superconductor applications.
- Bismuth oxychalcogenides are a class of emerging superconductors.
Purpose of the Study:
- To investigate the superconducting gap and pairing symmetry of Bi4O4S3.
- To determine the nature of superconductivity in this layered material.
- To compare experimental findings with existing theories like BCS.
Main Methods:
- Utilized the tunnel diode oscillator technique.
- Measured the temperature dependence of magnetic penetration depth.
- Analyzed superfluid density in the superconducting state.
Main Results:
- Bi4O4S3 exhibits characteristics of a conventional s-wave superconductor.
- A fully developed superconducting energy gap was observed.
- The zero-temperature gap value (Δ0) is 1.54 meV.
- The ratio 2Δ0/k(B)T(c) was found to be 7.2, exceeding the BCS prediction.
- Superfluid density aligns with a single-gap s-wave model.
Conclusions:
- Bi4O4S3 is confirmed as a conventional s-wave superconductor.
- The material displays strong-coupling superconductivity.
- The findings contribute to the understanding of unconventional superconducting behavior in layered materials.
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