First-principles computational prediction of new topological compound

Recent attempts at topological materials have revealed a large class of materials that show gapless surface states protected by time-reversal symmetry and crystal symmetries. Among them, topological insulating states protected by crystal symmetries, instead of time-reversal symmetry are classified as topological crystalline insulators. We computationally predict new 3-dimensional topological crystalline insulating compounds of space group 139(I/4mmm). We perform volume optimization by allowing to rearrange atomic positions and lattice parameters in performing the first principle density functional calculation with a generalized gradient approximation. Multiple Dirac crossings near X and P points on the Brillouin-zone near Fermi energy are identified by imposing spin-orbit coupling. Additionally, we performed formation energy, elastic properties, and phonon modes calculations to verify the structural, mechanical, and dynamic stability of the compound. Therefore, we suggest the compound for further investigation and experimental realization.