Discovery of the topological surface state in a noncentrosymmetric superconductor BiPd

TL;DR

This study identifies a topological surface state in the noncentrosymmetric superconductor BiPd through ARPES measurements, revealing a state at high binding energy but not near the Fermi level, impacting the understanding of topological superconductivity.

Contribution

The paper provides the first experimental evidence of a topological surface state in BiPd, a noncentrosymmetric superconductor, using ARPES and first-principles calculations.

Findings

Surface state at ~700 meV below Fermi level identified

Topological surface state confirmed by ARPES and calculations

No topological surface states near the Fermi level found

Abstract

Recently, noncentrosymmetric superconductor BiPd has attracted considerable research interest due to the possibility of being a topological superconductor. Here, we report a systematic high-resolution angle resolved photoemission spectroscopy (ARPES) study of the normal state electronic properties of BiPd. Our experimental results show the presence of a surface state at higher binding energy with the location of Dirac point at around 700 meV below the Fermi level. The detailed photon energy and temperature dependent measurements complemented by our first-principles calculations provide further evidence for the presence of the topological surface state at high binding energy. The absence of topological surface states near the Fermi level negates the possibility of the topological superconducting behavior in the surface of this material. Our first direct experimental discovery of a topological surface state in BiPd provides novel information that will guide the future search for topological superconductivity in noncentrosymmetric materials.