Fully gapped superconducting state in Au2Pb: a natural candidate for topological superconductor

Abstract

We measured the ultra-low-temperature specific heat and thermal conductivity of Au${}_2$Pb single crystal, a possible three-dimensional Dirac semimetal with a superconducting transition temperature $T_c\approx$ 1.05 K. The electronic specific heat can be fitted by a two-band s-wave model, which gives the gap amplitudes ${\Delta }_1$(0)/$k_B{T}_c$ = 1.38 and ${\Delta }_2$(0)/$k_B{T}_c$ = 5.25. From the thermal conductivity measurements, a negligible residual linear term ${\kappa }_0/T$ in zero field and a slow field dependence of ${\kappa }_0/T$ at low field are obtained. These results suggest that Au${}_2$Pb has a fully gapped superconducting state in the bulk, which is a necessary condition for topological superconductor if Au${}_2$Pb is indeed one.

arXiv comment6 pages, 4 figures

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Cited by in corpus (3)

• Superconducting density of states and bandstructure at the surface of the candidate topological superconductor Au2Pb
• Free-carrier dynamics in Au${}_2$Pb probed by optical conductivity measurements
• Emergence of Topological Superconductivity in Doped Topological Dirac Semimetals under Symmetry-Lowering Lattice Distortions