Stable Weyl points, trivial surface states and particle-hole compensation in WP2

TL;DR

This study combines ARPES and DFT to clarify WP2's electronic structure, revealing stable Weyl points and electron-hole compensation, which are key to understanding its topological properties and magneto-resistance.

Contribution

The paper provides the first detailed disentanglement of surface and bulk states in WP2, confirming the presence of stable Weyl points and electron-hole compensation through combined experimental and theoretical analysis.

Findings

Bulk bands are electron-hole compensated.

Presence of at least 4 temperature-independent Weyl points.

Surface states have different Fermi surface areas.

Abstract

A possible connection between extremely large magneto-resistance and the presence of Weyl points has garnered much attention in the study of topological semimetals. Exploration of these concepts in transition metal phosphide WP2 has been complicated by conflicting experimental reports. Here we combine angle-resolved photoemission spectroscopy (ARPES) and density functional theory (DFT) calculations to disentangle surface and bulk contributions to the ARPES intensity, the superposition of which has plagued the determination of the electronic structure in WP2. Our results show that while the hole- and electron-like Fermi surface sheets originating from surface states have different areas, the bulk-band structure of WP2 is electron-hole-compensated in agreement with DFT. Furthermore, the detailed band structure is compatible with the presence of at least 4 temperature-independent Weyl points, confirming the topological nature of WP2 and its stability against lattice distortions.