Dirac and Weyl Semimetal in XYBi (X=Ba, Eu; Y=Cu, Ag and Au)

TL;DR

This paper predicts that certain XYBi compounds are Dirac semimetals and proposes a method to realize Weyl semimetals by substituting Eu ions with Ba, using first-principles calculations and effective models.

Contribution

It introduces a new class of Dirac and Weyl semimetals in XYBi compounds and suggests a practical substitution approach to achieve Weyl semimetals.

Findings

BaYBi compounds are Dirac semimetals.

EuYBi compounds do not naturally split into Weyl points.

Substituting Eu with Ba can induce Weyl semimetal behavior.

Abstract

Weyl and Dirac semimetals recently stimulate intense research activities due to their novel properties. Combining first-principles calculations and effective model analysis, we predict that nonmagnetic compounds BaYBi (Y=Au, Ag and Cu) are Dirac semimetals. As for the magnetic compound EuYBi, although the time reversal symmetry is broken, their long-range magnetic ordering cannot split the Dirac point into pairs of Weyl points. However, we propose that partially substitute Eu ions by Ba ions will realize the Weyl semimetal.