Observation of Dirac state in half-Heusler material YPtBi

TL;DR

This study uses ARPES to identify a Dirac state in the half-Heusler superconductor YPtBi, revealing its topological properties and surface states, which could lead to new quantum phases and applications.

Contribution

First direct observation of a Dirac state in the half-Heusler compound YPtBi, linking topological states with superconductivity.

Findings

Dirac state located 500 meV below the chemical potential

Multiple Fermi surface pockets including hexagonal and half oval shapes

Presence of Rashba-split bands and surface states crossing the chemical potential

Abstract

The prediction of non-trivial topological electronic states hosted by half-Heusler compounds makes them prime candidates for discovering new physics and devices as they harbor a variety of electronic ground states including superconductivity, magnetism, and heavy fermion behavior. Here we report normal state electronic properties of a superconducting half-Heusler compound YPtBi using angle-resolved photoemission spectroscopy (ARPES). Our data reveal the presence of a Dirac state at the zone center of the Brillouin zone at 500 meV below the chemical potential. We observe the presence of multiple Fermi surface pockets including two concentric hexagonal and six half oval shaped pockets at the gamma and K points of the Brillouin zone, respectively. Furthermore, our measurements show Rashba-split bands and multiple surface states crossing the chemical potential which are supported by the first-principles calculations. Our finding of a Dirac state in YPtBi plays a significant role in establishing half-Heusler compounds as a new potential platform for novel topological phases and explore their connection with superconductivity.