Surface Fermi arc connectivity in the type-II Weyl semimetal candidate WTe$_{2}$

TL;DR

This study uses high-resolution photoemission to observe surface Fermi arcs in WTe2, revealing their connection to bulk states mediated by surface resonances, supporting its classification as a type-II Weyl semimetal.

Contribution

The paper provides experimental evidence of surface Fermi arcs in WTe2 and clarifies their connection to bulk states via surface resonances, supporting its topological classification.

Findings

Surface Fermi arcs connect bulk electron and hole pockets.

Surface resonances mediate the Fermi arc connectivity.

WTe2 is confirmed as a type-II Weyl semimetal.

Abstract

We perform ultrahigh resolution angle-resolved photoemission experiments at a temperature T=0.8 K on the type-II Weyl semimetal candidate WTe$_{2}$. We find a surface Fermi arc connecting the bulk electron and hole pockets on the (001) surface. Our results show that the surface Fermi arc connectivity to the bulk bands is strongly mediated by distinct surface resonances dispersing near the border of the surface-projected bulk band gap. By comparing the experimental results to first-principles calculations we argue that the coupling to these surface resonances, which are topologically trivial, is compatible with the classification of WTe$_{2}$ as a type-II Weyl semimetal hosting topological Fermi arcs. We further support our conclusion by a systematic characterization of the bulk and surface character of the different bands and discuss the similarity of our findings to the case of topological insulators.