The Fermi and Rashba energies of surface states in the Bi_xPb_{1-x}/Ag(111) alloy can be tuned simultaneously by changing the composition parameter x. We report on unconventional Fermi surface spin textures observed by spin and angle-resolved photoemission spectroscopy {that are correlated with a topological transition of the Fermi surface occurring at x=0.5. We show that the surface states remain fully spin polarized upon alloying and that the spin polarization vectors are approximately tangential to the constant energy contours. We discuss the implications of the topological transition for the transport of spin.
@article{arxiv.0903.0233,
title = {Unconventional Fermi surface spin textures in the Bi_xPb_{1-x}/Ag(111) surface alloy},
author = {Fabian Meier and Vladimir Petrov and Sebastian Guerrero and Christopher Mudry and Luc Patthey and Juerg Osterwalder and J. Hugo Dil},
journal= {arXiv preprint arXiv:0903.0233},
year = {2009}
}