Designing the Rashba spin texture by adsorption of inorganic molecules

Abstract

Using the physisorption and chemisorption of inorganic molecules on BiAg2/Ag(111) we demonstrate from first principles that the spin-orbit splitting and the spin direction of surface Rashba-split states can be manipulated selectively. Although NH3 is physisorbed, it nevertheless leads to a slight enhancement of the outward buckling of the surface Bi that increases the magnitude of the Rashba splitting. On the other hand, the weakly chemisorbed BH3 determines a strong inward relaxation of the surface Bi such that the occupied Rashba state shifts into Ag bulk states while a new unoccupied one is induced. Importantly, for the BH3-BiAg2/Ag(111) system the size of the out-of-plane spin polarization is significantly larger than the in-plane one at variance with the clean surface case.