Predicted remarkably topological nodal surface states in P63/m type Sr3WN3 from first-principles

Abstract

In this study, a new P63/m type material Sr3WN3 with excellent topological nodal surface (NS) state, i.e., the conduction and valence bands cross on closed NSs in the Brillouin zone (BZ), was predicted via first-principle calculation. The mentioned compound has mechanical and dynamic stability based on the calculated elastic constants and the observed phonon dispersion curves. Importantly, the NS of this material features the following advantages: (1) the energy variation of the NS is very small; (2) the energy of the NS is close to the Fermi level (EF); (3) no other energy bands observed near the EF. The orbital-resolved band structures of Sr3WN3 were calculated and we found that the NS states along A-L (H-A) and L-H directions are mainly formed from the N-p and W-d orbitals, respectively. Moreover, the effect of the spin–orbit coupling on the topological property were also discussed. We should point out the Sr3WN3 can be well described as a perfect TNS semimetal due to its SOC-induced gap sizes throughout the NS are less than 10 meV.