Temperature dependence of surface superconductivity in t-PtBi$_2$

Abstract

The Weyl semimetal trigonal PtBi$_2$ has recently been identified as a promising candidate material for intrinsic topological surface superconductivity emerging from the Fermi arc states of the material with a sizeable superconducting gap. We report the temperature evolution of the superconducting excitation spectrum using scanning tunneling spectroscopy in the range of $8-45\,$K. A large low-temperature gap in the order of $\Delta \approx 9\,$meV and a closing of the gap around $T_c \approx 45\,$K is observed. Thus, our results confirm the previously indicated high $T_c$-like superconductivity in t-PtBi$_2$.