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Strong Coupling Superconductivity in the Vicinity of the Structural Quantum Critical Point in (CaxSr1-x)3Rh4Sn13

Yu, Wing Chi, Cheung, Yiu Wing, Saines, Paul J., Imai, Masaki, Matsumoto, Takuya, Michioka, Chishiro, Yoshimura, Kazuyoshi, Goh, Swee K. (2015) Strong Coupling Superconductivity in the Vicinity of the Structural Quantum Critical Point in (CaxSr1-x)3Rh4Sn13. Physical Review Letters: Moving Physics Forward, 115 . p. 207003. ISSN 0031-9007. E-ISSN 1079-7114. (doi:10.1103/PhysRevLett.115.207003) (KAR id:51803)

Abstract

The family of the superconducting quasiskutterudites (CaxSr1?x)3Rh4Sn13 features a structural quantum critical point at xc=0.9, around which a dome-shaped variation of the superconducting transition temperature Tc is found. Using specific heat, we probe the normal and the superconducting states of the entire series straddling the quantum critical point. Our analysis indicates a significant lowering of the effective Debye temperature on approaching xc, which we interpret as a result of phonon softening accompanying the structural instability. Furthermore, a remarkably large enhancement of 2?/kBTc and ?C/?Tc beyond the Bardeen-Cooper-Schrieffer values is found in the vicinity of the structural quantum critical point. The phase diagram of (CaxSr1?x)3Rh4Sn13 thus provides a model system to study the interplay between structural quantum criticality and strong electron-phonon coupling superconductivity.

Item Type: Article
DOI/Identification number: 10.1103/PhysRevLett.115.207003
Uncontrolled keywords: Functional Materials Group
Subjects: Q Science > QC Physics > QC173.45 Condensed Matter
Divisions: Divisions > Division of Natural Sciences > Physics and Astronomy
Depositing User: Paul Saines
Date Deposited: 13 Nov 2015 09:37 UTC
Last Modified: 09 Dec 2022 06:43 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/51803 (The current URI for this page, for reference purposes)

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