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Point nodes persisting far beyond Tc in Bi2212.
Takeshi Kondo1, W Malaeb1, Y Ishida1
1ISSP, University of Tokyo, Kashiwa, Chiba 277-8581, Japan.
Nature Communications
|July 10, 2015
Summary
The nodal gap in cuprate superconductors survives above the critical temperature (Tc), indicating preformed pairs. Superconductivity emerges when pair-breaking rates fall below single-particle scattering rates.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Quantum Materials
Background:
- The superconducting mechanism in cuprates is key, with the pairing gap in the nodal region being crucial.
- A central question is whether the nodal state collapses at Tc or persists as preformed pairs above Tc.
Purpose of the Study:
- To investigate the behavior of the nodal gap in cuprates above the critical temperature (Tc).
- To determine if the point nodal state survives above Tc and understand its implications for superconductivity.
Main Methods:
- Utilized laser Angle-Resolved Photoemission Spectroscopy (ARPES) with ultrahigh-energy resolution.
- Analyzed temperature-dependent spectral evolution to track the nodal gap's behavior.
Main Results:
- Detected point nodes persisting well above Tc in Bi2212.
- Observed that superconductivity initiates when the pair-breaking rate becomes lower than the single-particle scattering rate upon cooling.
Conclusions:
- The point nodal state in cuprates does not collapse at Tc but survives as preformed pairs.
- The suppression of the pair-breaking rate relative to the single-particle scattering rate governs Tc in cuprates.
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