Distinct topological properties in Ce monopnictides having correlated f electrons: CeN vs. CeBi

Abstract

The hitherto-studied topological nature in Ce monopnictides (CePn) has been discussed based solely on their p-d band inversion, despite the existence of f electrons. Interestingly, however, we have found that CeN, the lightest CePn, has nontrivial Z2 topology originating from f -d band inversion. Through density-functional theory and dynamical mean-field theory calculations, we have demonstrated that, among the correlated f - electron systems of CePn, the lightest CeN is a coherent narrow f -band system having an f -d band-inverted topological Kondo insulator nature, whereas the heaviest CeBi is a strongly localized f -electron system having a conventional p-d band-inverted topological insulator nature. For CeN, topological surface states (TSSs) are identified clearly on three different (001), (110), and (111) surfaces. For CeBi, however, TSSs are identified only on the (111) surface. Furthermore, intriguing topological-crystalline insulator-type TSSs are identified on the (110) surfaces of both CeN and CeBi.