Strongly Ideal Robust Weyl Semimetals in Cubic Symmetry with Spatial-Inversion Breaking

TL;DR

This paper identifies a family of non-centrosymmetric cubic compounds with time-reversal symmetry that host robust ideal Weyl semimetal fermions, featuring well-separated Weyl nodes and long Fermi arcs, promising for topological applications.

Contribution

The study demonstrates that compounds with specific cubic symmetry and broken inversion symmetry can host ideal Weyl fermions with protected topological features, identified through first-principles calculations.

Findings

Compounds with formulas AB2, ABC, ABC2, and ABCD host Weyl fermions.

Weyl nodes are well separated in momentum space, preventing annihilation.

Long Fermi arcs connect Weyl nodes with opposite chirality.

Abstract

We show that compounds in a family that possess time-reversal symmetry and share a non-centrosymmetric cubic structure with the space group F-43m (No. 216) host robust ideal Weyl semi-metal fermions with desirable topologically protected features. The candidates in this family are compounds with different chemical formulas AB2, ABC, ABC2, and ABCD and their Fermi levels are predominantly populated by nontrivial Weyl fermions. Symmetry of the system requires that the Weyl nodes with opposite chirality are well separated in momentum space. Adjacent Weyl points have the same chirality, thus these Weyl nodes would not annihilate each other with respect to lattice perturbations. As Fermi arcs and surface states connect Weyl nodes with opposite chirality, the large separation of the latter in momentum space guarantees the appearance of very long arcs and surface states. This work demonstrates the use of system symmetry by first-principles calculations as a powerful recipe for discovering new Weyl semi-metals with attractive features whose protected fermions may be candidates of many applications.