Multi-band mass enhancement towards critical doping in a pnictide superconductor

Abstract Near critical doping, high-temperature superconductors exhibit multiple anomalies associated with enhanced electronic correlations and quantum criticality. Quasiparticle mass enhancement approaching optimal doping has been reported in quantum oscillation measurements in both cuprate and pni...

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Bibliographic Details
Published in:npj quantum materials 2019-02, Vol.4 (1), Article 8
Main Authors: Moir, Camilla Margaret, Riggs, Scott Chandler, Galvis, Jose Augusto, Lian, Xiujun, Giraldo-Gallo, Paula, Chu, Jiun-Haw, Walmsley, Philip, Fisher, Ian Randal, Shekhter, Arkady, Boebinger, Gregory Scott
Format: Article
Language:English
Subjects:
Anomalies
CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY
Critical point
Density of states
Doping
Group 5A compounds
High temperature superconductors
Magnetic fields
Magnetism
Phase diagrams
Superconductivity
Theory
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Summary:Abstract Near critical doping, high-temperature superconductors exhibit multiple anomalies associated with enhanced electronic correlations and quantum criticality. Quasiparticle mass enhancement approaching optimal doping has been reported in quantum oscillation measurements in both cuprate and pnictide superconductors. Although the data are suggestive of enhanced interactions, the microscopic theory of quantum oscillation measurements near a quantum critical point is not yet firmly established. It is therefore desirable to have a direct thermodynamic measurement of quasiparticle mass. Here we report high-magnetic field measurements of heat capacity in the doped pnictide superconductor BaFe 2 (As 1− x P x ) 2 . We observe saturation of the specific heat at high magnetic field in a broad doping range above optimal doping which enables a direct determination of the electronic density of states recovered when superconductivity is suppressed. Our measurements find a strong total mass enhancement in the Fermi pockets that superconduct. This mass enhancement extrapolates to a mass divergence at a critical doping of x  = 0.28.
ISSN:2397-4648
2397-4648
DOI:10.1038/s41535-018-0144-x