Electronic structure of topological superconductor candidate Au${}_{2}$Pb

TL;DR

This study combines experimental and theoretical methods to investigate the electronic structure of Au${}_{2}$Pb, a candidate topological superconductor, revealing surface states and Dirac-like dispersions that suggest topological properties.

Contribution

It provides new experimental ARPES data and DFT calculations demonstrating the presence of Dirac-like surface states in Au${}_{2}$Pb, supporting its potential as a topological superconductor.

Findings

Observation of surface states consistent with Dirac dispersion

Identification of structural phase transitions at specific temperatures

Evidence of topological surface states in ARPES measurements

Abstract

We use magnetization measurements, high-resolution angle-resolved photoemission spectroscopy (ARPES), and density functional theory (DFT) calculations to study the electronic properties of Au${}_{2}$Pb, a topological superconductor candidate. The magnetization measurements reveal three discontinuities at 40, 51, and 99~K that agree well with reported structural phase transitions. ARPES measurements of the Au${}_{2}$Pb (111) surface at 110~K shows a shallow hole pocket at the center and flower-petal-like surface states at the corners of the Brillouin zone. These observations match the results of DFT calculations relatively well. The flower-petal-like surface states appear to originate from a Dirac like dispersion close to the zone corner. For the Au${}_{2}$Pb (001) surface at 150~K, ARPES reveals at least one electron pocket between the $\Gamma$ and $M$ points, consistent with the DFT calculations. Our results provide evidence for the possible existence of Dirac state in this material.