Superconductivity in epitaxial PtSb(0001) thin films

Abstract

We report superconductivity in epitaxial PtSb(0001) thin films grown on SrF2(111). Electrical transport measurements reveal a superconducting transition at $T_{\mathrm c}=1.72$ K. The field-induced broadening of the transition and the presence of finite upper critical fields are consistent with type-II superconductivity. We determine the resistively defined upper critical fields for magnetic fields applied perpendicular and parallel to the film plane and parameterize their temperature dependence using an anisotropic Ginzburg-Landau approach. For the thickest film ($d=50$ nm), this yields coherence lengths of $\xi_{ab}\approx 55$ nm and $\xi_c\approx 14$ nm. Current-voltage characteristics show sizeable critical currents, with a critical current density reaching $J_{\mathrm c}\approx 6e4$ A/cm$^2$ at 0.5 K. These results establish epitaxial PtSb as a superconducting thin-film platform compatible with lattice-matched heterostructures in the NiAs-type materials family.