Identification of Topological Surface State in PdTe2 Superconductor by Angle-Resolved Photoemission Spectroscopy

TL;DR

This study uses angle-resolved photoemission spectroscopy and theoretical calculations to identify a topologically nontrivial surface state with a Dirac cone in PdTe2, a superconductor, revealing new potential for topological phenomena.

Contribution

First experimental discovery of a topological surface state with Dirac cone in PdTe2 superconductor, deep below the Fermi level, supported by theoretical calculations.

Findings

Topological surface state with Dirac cone identified in PdTe2

Dirac point located at ~1.75 eV below Fermi level

Surface state exhibits helical spin texture

Abstract

High resolution angle-resolved photoemission measurements have been carried out on transition metal dichalcogenide PdTe2 that is a superconductor with a Tc at 1.7 K. Combined with theoretical calculations, we have discovered for the first time the existence of topologically nontrivial surface state with Dirac cone in PbTe2 superconductor. It is located at the Brillouin zone center and possesses helical spin texture. Distinct from the usual three-dimensional topological insulators where the Dirac cone of the surface state lies at the Fermi level, the Dirac point of the surface state in PdTe2 lies deep below the Fermi level at ~1.75 eV binding energy and is well separated from the bulk states. The identification of topological surface state in PdTe2 superconductor deep below the Fermi level provides a unique system to explore for new phenomena and properties and opens a door for finding new topological materials in transition metal chalcogenides.