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

TL;DR

This study investigates the surface electronic properties of Au$_2$Pb, a candidate topological superconductor, using STM to measure the superconducting gap and density of states, revealing potential surface superconductivity.

Contribution

The paper provides experimental STM data on the superconducting surface states of Au$_2$Pb, highlighting the presence of a superconducting density of states at the Fermi level.

Findings

Superconducting gap measured on Au$_2$Pb surface.

Significant superconducting density of states at the Fermi level.

Discussion of possible surface state superconductivity.

Abstract

The electronic bandstructure of Au$_2$Pb has a Dirac cone which gaps when undergoing a structural transition into a low temperature superconducting phase. This suggests that the superconducting phase ($T_c=1.1$ K) might hold topological properties at the surface. Here we make Scanning Tunneling Microscopy experiments on the surface of superconducting Au$_2$Pb. We measure the superconducting gap and find a sizeable superconducting density of states at the Fermi level. We discuss possible origins for this finding in terms of superconductivity induced into surface states.