Coexistence of isotropic and extended s-wave order parameters in FeSe as revealed by low-temperature specific heat

Jiunn-Yuan Lin; Y. S. Hsieh; D. A. Chareev; A. N. Vasiliev; Y. Parsons; H. D. Yang

doi:10.1103/PhysRevB.84.220507

Coexistence of isotropic and extended s-wave order parameters in FeSe as revealed by low-temperature specific heat

Jiunn-Yuan Lin^*, Y. S. Hsieh, D. A. Chareev, A. N. Vasiliev, Y. Parsons, H. D. Yang

^*Corresponding author for this work

Institute of Physics

Research output: Contribution to journal › Article › peer-review

105 Scopus citations

Abstract

The comprehensive low-temperature specific-heat C(T) data identify both an isotropic s-wave and extended s-wave order parameters coexisting in a superconducting single-crystal FeSe with T _c = 8.11 K. The isotropic gap Δ ₀ = 1.33 meV on the hole Fermi sheets and the extended s-wave gap Δ = Δ _e(1+αcos2) with Δ _e = 1.13 meV and α = 0.78 on the electron Fermi sheets. The extended s wave is rather anisotropic, but the low-energy quasiparticle excitations demonstrate no sign of the accidental nodes. The coefficient γ(H) manifesting the quasiparticle contribution to C is a nonlinear function of the applied magnetic field H in the mixed state in accord with the anisotropic multiorder parameters.

Original language	English
Article number	220507
Journal	Physical Review B - Condensed Matter and Materials Physics
Volume	84
Issue number	22
DOIs	https://doi.org/10.1103/PhysRevB.84.220507
State	Published - 27 Dec 2011

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title = "Coexistence of isotropic and extended s-wave order parameters in FeSe as revealed by low-temperature specific heat",

abstract = "The comprehensive low-temperature specific-heat C(T) data identify both an isotropic s-wave and extended s-wave order parameters coexisting in a superconducting single-crystal FeSe with T c = 8.11 K. The isotropic gap Δ 0 = 1.33 meV on the hole Fermi sheets and the extended s-wave gap Δ = Δ e(1+αcos2) with Δ e = 1.13 meV and α = 0.78 on the electron Fermi sheets. The extended s wave is rather anisotropic, but the low-energy quasiparticle excitations demonstrate no sign of the accidental nodes. The coefficient γ(H) manifesting the quasiparticle contribution to C is a nonlinear function of the applied magnetic field H in the mixed state in accord with the anisotropic multiorder parameters.",

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T1 - Coexistence of isotropic and extended s-wave order parameters in FeSe as revealed by low-temperature specific heat

AU - Lin, Jiunn-Yuan

AU - Hsieh, Y. S.

AU - Chareev, D. A.

AU - Vasiliev, A. N.

AU - Parsons, Y.

AU - Yang, H. D.

PY - 2011/12/27

Y1 - 2011/12/27

N2 - The comprehensive low-temperature specific-heat C(T) data identify both an isotropic s-wave and extended s-wave order parameters coexisting in a superconducting single-crystal FeSe with T c = 8.11 K. The isotropic gap Δ 0 = 1.33 meV on the hole Fermi sheets and the extended s-wave gap Δ = Δ e(1+αcos2) with Δ e = 1.13 meV and α = 0.78 on the electron Fermi sheets. The extended s wave is rather anisotropic, but the low-energy quasiparticle excitations demonstrate no sign of the accidental nodes. The coefficient γ(H) manifesting the quasiparticle contribution to C is a nonlinear function of the applied magnetic field H in the mixed state in accord with the anisotropic multiorder parameters.

AB - The comprehensive low-temperature specific-heat C(T) data identify both an isotropic s-wave and extended s-wave order parameters coexisting in a superconducting single-crystal FeSe with T c = 8.11 K. The isotropic gap Δ 0 = 1.33 meV on the hole Fermi sheets and the extended s-wave gap Δ = Δ e(1+αcos2) with Δ e = 1.13 meV and α = 0.78 on the electron Fermi sheets. The extended s wave is rather anisotropic, but the low-energy quasiparticle excitations demonstrate no sign of the accidental nodes. The coefficient γ(H) manifesting the quasiparticle contribution to C is a nonlinear function of the applied magnetic field H in the mixed state in accord with the anisotropic multiorder parameters.

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DO - 10.1103/PhysRevB.84.220507

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Coexistence of isotropic and extended s-wave order parameters in FeSe as revealed by low-temperature specific heat

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