Point Node Gap Structure of Spin-Triplet Superconductor UTe2

Abstract

Low-temperature electrical and thermal transport, magnetic penetration depth, and heat capacity measurements were performed on single crystals of the actinide superconductor UTe2 to determine the structure of the superconducting energy gap. Heat transport measurements performed with currents directed along both crystallographic a- and b-axes reveal a vanishingly small residual fermionic component of the thermal conductivity. The magnetic field dependence of the residual term follows a rapid, quasi-linear increase consistent with the presence of nodal quasiparticles, rising toward the a-axis upper critical field where the Wiedemann-Franz law is recovered. Together with a quadratic temperature dependence of the magnetic penetration depth up to T/T_c=0.3, these measurements provide evidence for an unconventional spin-triplet superconducting order parameter with point nodes. Millikelvin specific heat measurements performed on the same crystals used for thermal transport reveal an upturn below 300 mK that is well described by a divergent quantum-critical contribution to the density of states (DOS). Modeling this contribution with a T^{-1/3} power law allows restoration of the full entropy balance in the superconducting state and a resultant cubic power law for the electronic DOS below T_c, consistent with the point-node gap structure determined by thermal conductivity and penetration depth measurements.

Comments: 6 pages, 4 figures

References in corpus (22)

• Spontaneously polarized half-gapped superconductivity
• Angular Position of Nodes in the Superconducting Gap of Quasi-2D Heavy-Fermion Superconductor CeCoIn_5
• Unconventional superconductivity in CeIrIn${}_5$ and CeCoIn${}_5$: Specific heat and thermal conductivity studies
• Magnetic Penetration Depth in Unconventional Superconductors
• Unconventional Superconductivity in Heavy Fermion UTe2
• Electronic thermal conductivity and the Wiedemann-Franz law for unconventional superconductors
• Extreme magnetic field-boosted superconductivity
• Heat Conduction in the Vortex State of NbSe_2: Evidence for Multi-Band Superconductivity
• Review of U-based Ferromagnetic Superconductors: Comparison between UGe2, URhGe, and UCoGe
• Universal heat conduction in the iron-arsenide superconductor KFe2As2 : Evidence of a d-wave state
• Coexistence of ferromagnetic fluctuations and superconductivity in the actinide superconductor UTe2
• Angular position of nodes in the superconducting gap of YBCO
• Metamagnetic Transition in Heavy Fermion Superconductor UTe2
• Unpaired Electrons in the Heavy-Fermion Superconductor CeCoIn_{5}
• Anisotropy of magnetothermal conductivity in Sr2RuO4
• Heat transport as a probe of superconducting gap structure
• Thermal Conductivity and Gap Structure of the Superconducting Phases of UPt3
• The Origin of Anomalous Low-Temperature Downturns in the Thermal Conductivity of Cuprates
• Superconducting Gap Structure of LaFePO Studied by Thermal Conductivity
• Fermi-Surface Instabilities in the Heavy-Fermion Superconductor UTe2
• Hybrid gap structure in the heavy-fermion superconductor CeIrIn${}_5$
• Dielectric Resonator Method For Determining Gap Symmetry Of Superconductors Through Anisotropic Nonlinear Meissner Effect

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