Dirac and Weyl Semimetal in XYBi (X=Ba, Eu; Y=Cu, Ag and Au)
  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. 
Yongping Du, Bo Wan, Di Wang, Li Sheng, Chun-Gang Duan and Xiangang   Wan
cond-mat.mtrl-sci cond-mat.mes-hall