Weyl semimetal phase in non-centrosymmetric transition metal monophosphides

TL;DR

This paper predicts that certain non-centrosymmetric transition metal monophosphides are Weyl semimetals with unique surface states, based on first-principles calculations, highlighting their potential for future experimental exploration.

Contribution

It identifies a family of nonmagnetic Weyl semimetals with specific Weyl points and surface states, expanding the understanding of topological phases in these materials.

Findings

Twelve pairs of Weyl points identified in each material.

Surface Fermi arc structures with unique shapes predicted.

Band inversions lead to Weyl points off mirror planes.

Abstract

Based on first principle calculations, we show that a family of nonmagnetic materials including TaAs, TaP, NbAs and NbP are Weyl semimetal (WSM) without inversion center. We find twelve pairs of Weyl points in the whole Brillouin zone (BZ) for each of them. In the absence of spin-orbit coupling (SOC), band inversions in mirror invariant planes lead to gapless nodal rings in the energy-momentum dispersion. The strong SOC in these materials then opens full gaps in the mirror planes, generating nonzero mirror Chern numbers and Weyl points off the mirror planes. The resulting surface state Fermi arc structures on both (001) and (100) surfaces are also obtained and show interesting shapes, pointing to fascinating playgrounds for future experimental studies.