Spin- and angle-resolved photoemission spectroscopy study of the Au(111) Shockley surface state

The spin character of the splitting of the Shockley surface state on Au(1 1 1) is directly verified by measurements of the in-plane and out-of-plane spin polarizations in angle-resolved photoemission spectra. The two parabolic sub-bands that are momentum-shifted with respect to each other, reveal a distinct, opposite spin polarization that within the errors lies in the surface plane. The measured in-plane orientation of the spin vectors is consistent with the simple spin structure expected from a nearly-free-electron model, where the polarization axis is tangential to the Fermi surface of the surface state. (C) 2004 Elsevier B.V. All rights reserved.