Combined large spin splitting and one-dimensional confinement in surface alloys

We have found and characterized, by angle-resolved photoelectron spectroscopy (ARPES), quasi-one-dimensional spin-split states in chain-like surface alloys formed by large Z elements (Bi and Pb) at the Cu(110) surface. The ARPES results are supported by first-principles relativistic calculations, which also confirm the spin polarization of these states, characteristic of the Rashba-Bychkov effect. The Fermi surface contours are open, but warped, as a result of the interaction with the bulk Cu conduction band. This interaction introduces a k dependence of the spin splitting perpendicular to the chains direction. We have also investigated the influence of the atomic spin-orbit parameter in substitutional isostructural Bi-1-Pb-x(x) overlayers, and found that the magnitude of the spin splitting can be continuously tuned as a function of stoichiometry.