Specific Heat and Critical Behavior in BaFe<sub>2</sub>(As<sub>1-x</sub>P<sub>x</sub>)<sub>2</sub>

 · Invited

Abstract

With Tc’s below 40 K and evidence of a quantum critical point [1], the iron-based high-temperature superconductor BaFe2(As1-xPx)2 is an appealing system for investigating the behavior underlying superconductivity in high-Tc superconductors. By applying magnetic fields up to 35 T, we are able to suppress superconductivity and reveal the normal state of overdoped BaFe2(As1-xPx)2. We observe √H behavior indicating a nodal superconducting gap, saturation of the heat capacity at a magnetic field corresponding to the onset of the normal state, and enhancement of the quasiparticle mass sum as calculated from electronic specific heat coefficient as optimal doping is approached [1]. Our comparison of specific heat as a function of magnetic field to specific heat as a function of temperature, as well as other measurements, forms a consistent treatment of specific heat measurements in high-temperature superconductors.

[1] K. Hashimoto et al. A Sharp Peak of the Zero-Temperature Penetration Depth at Optimal Composition in BaFe2(As1–xPx)2 Science 336, 1554-1557 (2012)
[2] C. M. Moir et al. Multi-band mass enhancement towards critical doping in a pnictide superconductor npj Quantum Materials 4, 8 (2019)

*BaFe2(As1-xPx)2 samples were grown at the The Geballe Laboratory for Advanced Materials at Stanford University supported by the Department of Energy, Office of Basic Energy Sciences under contract DE-AC02-76SF00515 and the Gordon and Betty Moore Foundation. DC-field measurements were performed at the DC Magnet Facility of the National High Magnetic Field Laboratory (NHMFL) in Tallahassee, FL. Thermometer calibrations were performed in the Pulsed Field Facility of the NHMFL in Los Alamos, NM. The work at the NHMFL was supported through the National Science Foundation Cooperative Agreements DMR-1157490 and DMR-1644779, the United States Department of Energy, and the State of Florida.

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Presenters

  • Camilla Moir

    • University of California, San Diego
    • Physics, University of California San Diego

Authors

  • Camilla Moir

    • University of California, San Diego
    • Physics, University of California San Diego

  • Scott C. Riggs

    • NHMFL

  • Jose A Galvis

    • NHMFL

  • Paula Giraldo-Gallo

    • Departamento de Física, Universidad de los Andes
    • University of Los Andes
    • UNIVERSIDAD DE LOS ANDES
    • Universidad de los Andes

  • Jiun-Haw Chu

    • University of Washington
    • Department of Physics, University of Washington, Seattle
    • Department of Physics, University of Washington
    • Physics, University of Washington

  • Philip Walmsley

    • Stanford University

  • Ian R Fisher

    • Geballe Laboratory for Advanced Materials, Stanford University
    • Stanford Univ
    • Stanford University
    • Department of Applied Physics, Stanford University

  • Arkady Shekhter

    • NHMFL
    • National High Magnetic Field Lab

  • Greg Scott Boebinger

    • NHMFL