Topological Crystalline Insulators and Dirac Octets in Anti-perovskites
  We predict a new class of topological crystalline insulators (TCI) in the anti-perovskite material family with the chemical formula A$_3$BX. Here the nontrivial topology arises from band inversion between two $J=3/2$ quartets, which is described by a generalized Dirac equation for a "Dirac octet". Our work suggests that anti-perovskites are a promising new venue for exploring the cooperative interplay between band topology, crystal symmetry and electron correlation. 
Timothy H. Hsieh, Junwei Liu, and Liang Fu
cond-mat.str-el cond-mat.mtrl-sci