Bulk and surface electronic structure of the dual-topology semimetal Pt2HgSe3

TL;DR

This study investigates the electronic structure of Pt2HgSe3, revealing a gapped Dirac nodal line and topological surface states, indicating a coexistence of topological crystalline and weak topological phases.

Contribution

It provides high-resolution experimental data and theoretical analysis demonstrating the coexistence of multiple topological phases in Pt2HgSe3.

Findings

Identification of a gapped Dirac nodal line

Observation of topological surface states with van Hove singularities

Evidence of coexistence of topological crystalline and weak topological phases

Abstract

We report high-resolution angle resolved photoemission measurements on single crystals of Pt2HgSe3 grown by high-pressure synthesis. Our data reveal a gapped Dirac nodal line whose (001)-projection separates the surface Brillouin zone in topological and trivial areas. In the non-trivial $k$-space range we find surface states with multiple saddle-points in the dispersion resulting in two van Hove singularities in the surface density of states. Based on density functional theory calculations, we identify these surface states as signatures of a topological crystalline state which coexists with a weak topological phase.