Quantitative vectorial spin analysis in angle-resolved photoemission:Bi∕Ag(111)andPb∕Ag(111)

Abstract

The concept of vectorial spin analysis in spin and angle-resolved photoemission is illustrated in this paper. Two prototypical systems, $\mathrm{Bi}∕\mathrm{Ag}\left(111\right)(\sqrt{3}\times \sqrt{3})R30°$ and $\mathrm{Pb}∕\mathrm{Ag}\left(111\right)(\sqrt{3}\times \sqrt{3})R30°$, which show a large Rashba-type spin-orbit splitting, were investigated by means of spin and angle-resolved photoemission. The spin polarization vectors of individual bands were determined by a two-step fitting routine. First, the measured intensities are fitted with an appropriate number of suitable peaks to quantify the contributions of the individual bands; then, the measured spin polarization curves are fitted by varying the polarization direction and its magnitude for each band. We confirm that the surface states experience a large spin splitting. Moreover, we find that all surface state bands are 100% spin polarized, and that for some states, spin polarization vectors rotate out of the surface plane.