Robust Type-II Weyl Semimetal Phase in Transition Metal Diphosphides XP$_2$ (X = Mo, W)

TL;DR

This paper predicts a robust type-II Weyl semimetal phase in transition metal diphosphides MoP$_2$ and WP$_2$, characterized by simple band structures, long Fermi arcs, and potential for observing unique chiral anomalies.

Contribution

It introduces the prediction of a stable type-II Weyl semimetal phase in MoP$_2$ and WP$_2$, with specific topological features and experimental accessibility.

Findings

Presence of four pairs of type-II Weyl points in MoP$_2$ and WP$_2$

Same chirality of neighboring Weyl points enhances robustness

Long topological Fermi arcs suitable for ARPES detection

Abstract

The recently discovered type-II Weyl points appear at the boundary between electron and hole pockets. Type-II Weyl semimetals that host such points are predicted to exhibit a new type of chiral anomaly and possess thermodynamic properties very different from their type-I counterparts. In this Letter, we describe the prediction of a type-II Weyl semimetal phase in the transition metal diphosphides MoP$_2$ and WP$_2$. These materials are characterized by relatively simple band structures with four pairs of type-II Weyl points. Neighboring Weyl points have the same chirality, which makes the predicted topological phase robust with respect to small perturbations of the crystalline lattice. In addition, this peculiar arrangement of the Weyl points results in long topological Fermi arcs, thus making them readily accessible in angle-resolved photoemission spectroscopy.