Superconducting density of states and band structure at the surface of the candidate topological superconductor Au2Pb

[EN] The electronic band structure of Au2Pb has a Dirac cone which gaps when undergoing a structural transition into a low temperature superconducting phase. This suggests that the superconducting phase (Tc = 1.1 K) might hold topological properties at the surface. Here we make Scanning Tunneling Microscopy experiments on the surface of superconducting Au2Pb. We measure the superconducting gap and find a sizable superconducting density of states at the Fermi level. We discuss possible origins for this finding in terms of superconductivity induced into surface states.This work was supported by the Spanish Research State Agency (Grants No. PID2020-114071RB-I00, No. FIS2017-84330-R, No. CEX2018-000805-M, No. RYC-2014-15093, and No. MAT2017-87134-C2-2-R), by the Comunidad de Madrid through program NANOFRONTMAG-CM (Grant No. S2013/MIT-2850), by the European Research Council PNICTEYES Grant Agreement No. 679080 and by the Swedish Research Council (Vetenskapsrådet Grant No. 2018-03488). F.M. and M.G.H. acknowledge European Union’s Horizon 2020 research and innovation program Grant Agreement No. 881603 Graphene Core3-Graphene-based disruptive technologies, EU FLAG-ERA through the project To2Dox, JTC-2019-009 and the Comunidad de Madrid through the project CAIRO-CM project, Y2020/NMT-6661.We acknowledge collaborations through EU program Cost CA16218 (Nanocohybri). J.J.B. acknowledges the Marie Curie Fellowship program (H2020 MSCA-IF2016-751047) and the Generalitat Valenciana (CDEIGENT/2019/022). Ames Laboratory is operated for the U.S. Department of Energy by Iowa State University under Contract No. DE-AC02-07CH11358. We acknowledge SEGAINVEX at UAM for design and construction of cryogenic equipment.Peer reviewe