Figure 4: Comparison between conventional Rashba (R-1) and local Rashba (R-2) effects.

(a) R-1 Rashba effect in non-centrosymmetric materials. The inversion symmetry is broken and there is a net dipole field. The right panel shows schematically the typical spin-resolved band structure induced by R-1 Rashba effect with a spin splitting in energy. (b) R-2 Rashba effect in centrosymmetric materials. The inversion symmetry is preserved and there is a local site dipole field in spite of the vanishing total dipole field. The right panels illustrate the schematic spin texture induced by R-2 Rashba effect. The two kinds of spin texture with opposite helicities are spatially separated in different layers, resulting in overall zero spin polarization.