Fully gapped pairing state in spin-triplet superconductor UTe${}_2$

Abstract

Spin-triplet superconductors provide an ideal platform for realizing topological superconductivity with emergent Majorana quasiparticles. The promising candidate is the recently discovered superconductor UTe${}_2$, but the symmetry of the superconducting order parameter remains highly controversial. Here we determine the superconducting gap structure by the thermal conductivity of ultra-clean UTe${}_2$ single crystals. We find that the $a$ axis thermal conductivity divided by temperature $\kappa /T$ in zero-temperature limit is vanishingly small for both magnetic fields $\mathbf{H}||a$ and $\mathbf{H}||c$ axes up to $H/H_{c2}\sim 0.2$, demonstrating the absence of any types of nodes around $a$ axis contrary to the previous belief. The present results, combined with the reduction of the NMR Knight shift in the superconducting state, indicate that the superconducting order parameter belongs to the isotropic $A_u$ representation with a fully gapped pairing state, analogous to the B phase of superfluid ${}^3$He. These findings reveal that UTe${}_2$ is likely to be a long-sought three-dimensional (3D) strong topological superconductor characterized by a 3D winding number, hosting helical Majorana surface states on any crystal plane.

arXiv comment10pages, 4 figures

References in corpus (47)

• Fault-tolerant quantum computation by anyons
• Non-abelian statistics of half-quantum vortices in p-wave superconductors
• Topological superconductors: a review
• Spontaneously polarized half-gapped superconductivity
• Superconductivity on the border of weak itinerant ferromagnetism in UCoGe
• Angular Position of Nodes in the Superconducting Gap of Quasi-2D Heavy-Fermion Superconductor CeCoIn_5
• Microscopic evidence for a chiral superconducting order parameter in the heavy fermion superconductor UTe2
• Unconventional Superconductivity in Heavy Fermion UTe2
• Extreme magnetic field-boosted superconductivity
• Universal Heat Conduction in YBa_2Cu_3O_6.9
• Exotic Superconducting Properties in the Electron-Hole Compensated Heavy Fermion `Semimetal' URu2Si2
• Unconventional Superconductivity in UTe2
• Nodal Structure of Unconventional Superconductors Probed by the Angle Resolved Thermal Transport Measurements
• Field-reentrant superconductivity close to a metamagnetic transition in the heavy-fermion superconductor UTe${}_2$
• Insulator-metal transition and topological superconductivity in UTe2 from a first-principles calculation
• Point Node Gap Structure of Spin-Triplet Superconductor UTe2
• Superconducting Properties of Heavy Fermion UTe${}_2$ Revealed by ${}^{125}$Te-Nuclear Magnetic Resonance
• Low energy band structure and symmetries of UTe2 from angle resolved photoemission spectroscopy
• Single-component superconducting state in UTe2 at 2 K
• Specific heat measurements of the gap structure of the organic superconductors kappa-(ET)_2Cu[N(CN)_2]Br and kappa-(ET)_2Cu(NCS)_2
• First Observation of de Haas-van Alphen Effect and Fermi Surfaces in Unconventional Superconductor UTe2
• Fully gapped superconductivity with no sign change in the prototypical heavy-fermion CeCu2Si2
• Anomalous quasiparticle transport in the superconducting state of CeCoIn5
• Direct Observation and Anisotropy of the Contribution of Gap nodes in the Low Temperature Specific Heat of YBa_2Cu_3O_7
• Thermal Conductivity and Gap Structure of the Superconducting Phases of UPt3
• Large Reduction in the $a$-axis Knight Shift on UTe${}_2$ with $T_{\mathrm{c}}$ = 2.1 K
• Superconducting order parameter in UTe${}_2$ determined by Knight shift measurement
• Field-induced tuning of the pairing state in a superconductor
• Anomalous normal fluid response in a chiral superconductor UTe2
• Anisotropic response of spin susceptibility in the superconducting state of UTe${}_2$ probed with ${}^{125}$Te-NMR measurement
• Chiral superconductivity in UTe2 probed by anisotropic low-energy excitations
• Spatially inhomogeneous superconductivity in UTe2
• Mixed-state quasiparticle transport in high-T_c cuprates: localization by magnetic field
• Orientation of point nodes and nonunitary triplet pairing tuned by the easy-axis magnetization in UTe2
• Comparison of two superconducting phases induced by a magnetic field in UTe2
• Electronic Structure of UTe${}_2$ Studied by Photoelectron Spectroscopy
• $c$-axis transport in UTe${}_2$: Evidence of Three Dimensional Conductivity Component
• Nodeless superconductivity in Ca3Ir4Sn13: evidence from quasiparticle heat transport
• Fermi-Surface Instabilities in the Heavy-Fermion Superconductor UTe2
• Random magnetic field and quasi-particle transports in the mixed state of high T_{c} cuprates
• Slow Electronic Dynamics in the Paramagnetic State of UTe${}_2$
• Microscopic imaging homogeneous and single phase superfluid density in UTe${}_2$
• Ubiquitous Spin Freezing in the Superconducting State of UTe2
• Thermodynamic and electrical transport properties of UTe${}_2$ under uniaxial stress
• Subdominant interactions and Hc2 in UBe13
• Anisotropic Enhancement of Lower Critical Field in Ultraclean Crystals of Spin-Triplet Superconductor UTe2
• Low temperature specific heat and thermal conductivity in superconducting UTe2

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• Pair Wavefunction Symmetry in UTe2 from Zero-Energy Surface State Visualization
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• Nodal superconducting gap structure and topological surface states of UTe${}_2$
• Theoretical studies on off-axis phase diagrams and Knight shifts in UTe${}_2$ -- Tetra-critical point, d-vector rotation, and multiple phases
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• Microscopic theory of pair density waves in spin-orbit coupled Kondo lattice
• Magnetic signatures of pressure-induced multicomponent superconductivity in UTe${}_2$
• Thermal conductivity of nonunitary triplet superconductors: application to UTe${}_2$
• Higher-order topological phases for time-reversal-symmetry breaking superconductivity in UTe${}_2$
• Reciprocal and nonreciprocal paraconductivity in bilayer multiphase superconductors
• Two-dimensional flat band on the (011) surface of UTe${}_2$: Implication for STM measurements with a superconducting tip
• $b$-axis and $c$-axis Knight shift measurements in the superconducting state on ultraclean UTe${}_2$ with $T_c$ = 2.1 K
• Visualizing the Odd-parity Superconducting Order Parameter and its Quasiparticle Surface Band in UTe2
• Revealing isotropic abundant low-energy excitations in UTe${}_2$ through complex microwave surface impedance
• Nodal Superconductivity of UTe${}_2$ Probed by Field-Angle-Resolved Specific Heat on a Crystal with $T_{\mathrm{c}}=2.1$ K
• Raman response of collective modes in multicomponent superconductors
• Electronic structure of UTe${}_2$ under pressure
• Spin-lattice relaxation for point-node-like s-wave superconductivity in f-electron systems
• Quasiparticle Interference of Spin-Triplet Superconductors: Application to UTe${}_2$
• Theoretical Study of Impurity Effects on Superconductivity in UTe2
• Resolving the Thermal Paradox: Many-body localization or fractionalization?