Superconducting properties of the spin Hall candidate Ta3Sb with eightfold degeneracy

Abstract

We report the synthesis and characterization of phase pure Ta3Sb, a material predicted to be topological with eightfold degenerate fermionic states [Science 353, aaf5037 (2016)] and to exhibit a large spin Hall effect [Sci. Adv. 5, eaav8575 (2019]. We observe superconductivity in Ta3Sb with Tc~ 0.67 K in both electrical resistivity \r{ho}(T) and specific heat C(T) measurements. Field dependent measurements yield the superconducting phase diagram with an upper critical field of Hc2(0) ~ 0.95 T, corresponding to a superconducting coherence length of ξ ~18.6 nm. The gap ratio deduced from specific heat anomaly, 2Δ0/kBTc is 3.46, a value close to the Bardeen-Cooper-Schrieffer (BCS) value of 3.53. From a detailed analysis of both the transport and thermodynamic data within the Ginsburg-Landau (GL) framework, a GL parameter of \k{appa} ~90 is obtained identifying Ta3Sb as an extreme type-II superconductor. The observation of superconductivity in an eightfold degenerate fermionic compound with topological surface states and predicted large spin Hall conductance positions Ta3Sb as an appealing platform to further explore exotic quantum states in multifold degenerate systems.

arXiv comment16 Pages, 3 figures

References in corpus (27)

• Signatures of Majorana fermions in hybrid superconductor-semiconductor nanowire devices
• Discovery of a Three-dimensional Topological Dirac Semimetal, Na3Bi
• Experimental discovery of Weyl semimetal TaAs
• Topological superconductors: a review
• Beyond Dirac and Weyl fermions: Unconventional quasiparticles in conventional crystals
• Observation of topological superconductivity on the surface of an iron-based superconductor
• Spontaneously polarized half-gapped superconductivity
• Microscopic evidence for a chiral superconducting order parameter in the heavy fermion superconductor UTe2
• Universality of the Mott-Ioffe-Regel limit in metals
• Double Dirac Semimetals in Three Dimensions
• Superconductivity in the A15 Structure
• Topological Dirac States and Pairing Correlations in the Non-Centrosymmetric Superconductor PbTaSe2
• Nematic superconductivity in doped Bi2Se3 topological superconductors
• Predicted Realization of Cubic Dirac Fermion in Quasi-One-Dimensional Transition-Metal MonoChalcogenides
• Giant Intrinsic Spin Hall Effect in W${}_3$Ta and other A15 Superconductors
• Orbital and spin effects for the upper critical field in As deficient disordered Fe pnictide superconductors
• Optical signatures of multifold fermions in the chiral topological semimetal CoSi
• Extremely high conductivity observed in the triple point topological metal MoP
• Membrane-based nanocalorimeter for high-resolution measurements of low-temperature specific heat
• Surface Contribution to the Superconducting Properties of MgB2 Single Crystals
• Observation of Topological Surface State in High Temperature Superconductor MgB2
• Topological states in A15 superconductors
• Fermions and bosons in nonsymmorphic PdSb2 with sixfold degeneracy
• Observation of sixfold degenerate fermions in PdSb${}_2$
• Study of the superconducting ground state of topological superconducting candidates Ti${}_3$X (X = Ir, Sb)
• Triple point fermions in ferroelectric GeTe
• ${}^{57}$Fe Mössbauer study of stoichiometric iron based superconductor CaKFe${}_4$As${}_4$: a comparison to KFe${}_2$As${}_2$ and CaFe${}_2$As${}_2$

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• A15 Phase Ta3Sb Thin Films: Direct Synthesis, Charge Transport and Spin-Orbit Torque