The layered compound γ-PtBi2 is a topological semimetal with Fermi arcs at the surface joining bulk Weyl points. Recent work has found signatures of surface superconductivity consisting of gap openings compatible with a critical temperature orders of magnitude larger than the bulk value. However, no superconducting vortices have been identified, raising questions about the robustness of the phase coherence. Here we use very low temperature Scanning Tunneling Microscopy (STM) and find robust superconductivity with TC=2.9 K and HC2≈1.8 T linked to the Fermi arcs. We observe quantized superconducting vortices, demonstrating two-dimensional macroscopic quantum phase coherence.
@article{arxiv.2508.04867,
title = {Robust two-dimensional surface superconductivity and vortex lattice in the Weyl semimetal $\gamma$-PtBi$_2$},
author = {Jose Antonio Moreno and Pablo García Talavera and Edwin Herrera and Sara López Valle and Zhuoqi Li and Lin-Lin Wang and Sergey Bud'ko and Alexander I. Buzdin and Isabel Guillamón and Paul C. Canfield and Hermann Suderow},
journal= {arXiv preprint arXiv:2508.04867},
year = {2026}
}