Hidden spin polarization in nonmagnetic centrosymmetric BaNiS2 crystal: Signatures from first principles

The recent discovery of hidden spin polarization emerging in bulk electronic states of specific nonmagnetic crystals is a fascinating phenomenon, though hardly explored yet. Here, we study from a theoretical perspective nonmagnetic BaNiS2, recently suggested to exhibit a giant Rashba-like spin-orbit splitting of the bulk bands, despite the absence of heavy elements. We employ density functional theory and Green's functions calculations to reveal the exact spin textures of both bulk and surface. We predict unambiguous signatures of spin-polarized electronic states at the surface, which reflect the bulk Rashba splitting and which could be experimentally measured with sufficient resolution: this would constitute a clear report of a bulk-Rashba-induced spin splitting at the surface of centrosymmetric crystals.