Role of Fermi surface anisotropy in the study of gap anisotropy using magnetic-field-angle dependence of thermal oscillations in AyFe2-xSe2 superconductors

Abstract

We present a numerical study of the field-angle resolved oscillations of the thermal conductivity and specific heat under rotated magnetic field in the $A_y$Fe${}_{2-x}$Se${}_2$ [$A$=K,Rb,Cs,(Tl,K)] superconductors, using realistic two-band Fermi surface parameterization. Our key finding is that even for isotropic pairing on an anisotropic Fermi surface, the thermodynamic quantities exhibit substantial oscillatory behavior in the superconducting state, even much below the upper critical field. Furthermore, in multiband systems the competition of anisotropies between two Fermi surfaces can cause a double sign reversal of oscillations as a function of temperature, irrespective of gap anisotropy. Our findings put severe constraints on simple interpretations of field-angle resolved measurements widely used to identify the angular structure of the superconducting gap.

arXiv comment5 pages, 3 figures (v2): revised text, supplementary material: Accepted in PRL

References in corpus (43)

• Unconventional sign-reversing superconductivity in LaFeAsO_(1-x)F_x
• Magnetism, superconductivity, and pairing symmetry in Fe-based superconductors
• Pnictogen height as a possible switch between high-T_c nodeless and low-T_c nodal pairings in the iron based superconductors
• Reply to Comment on "Unconventional s-wave superconductivity in Fe(Se,Te)"
• Fe-based high temperature superconductivity with Tc=31K bordering an insulating antiferromagnet in (Tl,K)FexSe2 Crystals
• Synthesis and crystal growth of Cs0.8(FeSe0.98)2: a new iron-based superconductor with Tc=27K
• Electronic thermal conductivity and the Wiedemann-Franz law for unconventional superconductors
• Superconducting Gap Structure of Spin-Triplet Superconductor Sr_2RuO_4 Studied by Thermal Conductivity
• d-wave pairing from spin fluctuations in the KxFe{2-y}Se2 superconductors
• Nodal Structure of Unconventional Superconductors Probed by the Angle Resolved Thermal Transport Measurements
• Sign reversal of field-angle resolved heat capacity oscillations in a heavy fermion superconductor CeCoIn${}_5$ and $d_{x^2-y^2}$ pairing symmetry
• The Electron Pairing of K${}_x$Fe${}_{2-y}$Se${}_2$
• Evolution of superconductivity in Fe-based systems with doping
• Strong nodeless pairing on separate electron Fermi surface sheets in (Tl, K)Fe${}_{1.78}$Se${}_2$ probed by ARPES
• Angular position of nodes in the superconducting gap of YBCO
• Field-angle Dependence of the Zero-Energy Density of States in the Unconventional Heavy-Fermion Superconductor CeCoIn5
• Determination of the Superconducting Gap Structure in All Bands of the Spin-Triplet Superconductor Sr2RuO4
• Symmetry analysis of possible superconducting states in KxFe2Se2 superconductors
• Possible pairing states of the Fe-based superconductors
• Electronic structures and magnetic orders of Fe-vacancies ordered ternary iron selenides TlFe${}_{1.5}$Se${}_2$ and AFe${}_{1.5}$Se${}_2$ (A=K, Rb, or Cs)
• Direct Observation of Nodal Quasiparticles in an Unconventional Superconductor: Field-angle Dependent Heat Capacity of YNi2B2C
• Nodal structure of quasi-2D superconductors probed by magnetic field
• Anisotropic Structure of the Order Parameter in FeSe0.45Te0.55 Revealed by Angle Resolved Specific Heat
• Quasiparticle thermal conductivity in the vortex state of high-T${}_c$ cuprates
• 77Se NMR Investigation of the K(x)Fe(2-y)Se(2) High Tc Superconductor (Tc=33K)
• Twofold spontaneous symmetry breaking in a heavy fermion superconductor UPt${}_3$
• Emergence of Fully-Gapped $s_{++}$-wave and Nodal d-wave States Mediated by Orbital- and Spin-Fluctuations in Ten-Orbital Model for KFe${}_2$Se${}_2$
• Robustness of s-wave Pairing in Electron-Overdoped ${\text{A}}_{1-y}{\text{Fe}}_{2-x}{\text{Se}}_2$
• Orientational field-dependence of low-lying excitations in mixed state of unconventional superconductors
• Stripes, spin resonance and $d_{x^2-y^2}-$pairing symmetry in FeSe-based layered superconductors
• Superconducting properties of single-crystalline A_{x}Fe_{2-y}Se_{2} (A=Rb, K) studied using muon spin spectroscopy
• Unconventional superconductors under rotating magnetic field I: density of states and specific heat
• Spectrum of low energy excitations in the vortex state: comparison of Doppler shift method to quasiclassical approach
• Unconventional superconductors under rotating magnetic field II: thermal transport
• Electronic Structure of KFe${}_2$Se${}_2$ from First Principles Calculations
• Theory of thermal conductivity in extended-$s$ state superconductors: application to ferropnictides
• Probing the nodal gap in the pressure-induced heavy fermion superconductor CeRhIn5
• Possible Superconducting Symmetry and Magnetic Correlations in K0.8Fe2Se2: A 77Se-NMR Study
• Theory of quasiparticle vortex bound states in Fe-based superconductors: application to LiFeAs
• Modulated superconductivity due to vacancy and magnetic order in $A_x$Fe${}_{2-x/2}$Se${}_2$ [$A=$Cs, K, (Tl,Rb), (Tl,K)] iron-selenide superconductors
• Quasiclassical Approach to Transport in the Vortex State and the Hall Effect
• Nodes vs. minima in the energy gap of iron-pnictides from field-induced anisotropy
• Heat-Capacity Measurements of Energy-Gap Nodes of the Heavy-Fermion Superconductor CeIrIn5 Deep inside the Pressure-Dependent Dome Structure of its Superconducting Phase Diagram

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