Surface Alloys: A Class of Materials with Giant Rashba Spin-Orbit Coupling

The surface alloy Bi/Ag( 111) exhibits a giant spin splitting of its surface electronic structure due to Rashba spin-orbit coupling. Electronic structure calculations prove that the effect is brought about by an in-plane structural inversion asymmetry in the surface layer, in interplay with the conventional Rashba effect. These findings pave the way for testing theoretical predictions for spin-orbit split two-dimensional electron gases.