  Given the rarity of metallic systems that exhibit ferroelectric-like
transitions, it is apparently challenging to find a system that simultaneously
possesses superconductivity and ferroelectric-like structural instability.
Here, we report the observation of superconductivity at 2.4 K in a layered
semimetal SrAuBi characterized by strong spin-orbit coupling (SOC) and
ferroelectric-like lattice distortion. Single crystals of SrAuBi have been
successfully synthesized and found to show a polar-nonpolar structure
transition at 214 K, which is associated with the buckling of Au-Bi honeycomb
lattice. On the basis of the band calculations considering SOC, we found
significant Rashba-type spin splitting and symmetry-protected multiple Dirac
points near the Fermi level. We believe that this discovery opens up new
possibilities of pursuing exotic superconducting states associated with the
semimetallic band structure without space inversion symmetry and the
topological surface state with the strong SOC.
