CaTe: a new topological node-line and Dirac semimetal
  Topological semimetals recently stimulate intense research activities. Combining first-principles calculations and effective model analysis, we predict that CaTe is topological node-line semimetal when spin-orbit coupling (SOC) is ignored. We also obtain the nearly flat surface state which has the drumhead characteristic. When SOC is included, three node lines evolve into a pair of Dirac points along the $M-R$ line. These Dirac points are robust and protected by $C_{4}$ rotation symmetry. Once this crystal symmetry is broken, the Dirac points will be eliminated, and the system becomes a strong topological insulator. 
Yongping Du, Feng Tang, Di Wang, Li Sheng, Er-jun Kan, Chun-Gang Duan,   Sergey Y. Savrasov and Xiangang Wan
cond-mat.mtrl-sci