  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-x}Pb_{x} overlayers, and found
that the magnitude of the spin splitting can be continuously tuned as a
function of stoichiometry.
