Berlin 2015 – scientific programme

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O: Fachverband Oberflächenphysik

O 88: Electronic Structure: Surface Magnetism and Spin Phenomena

O 88.6: Talk

Thursday, March 19, 2015, 16:15–16:30, MA 042

Spin-orbit entanglement in the Bi/Ag(111) surface alloy — •Thiago Ribeiro Fonseca Peixoto, Henriette Maaß, Christoph Seibel, Hendrik Bentmann, and Friedrich Reinert — Physikalisches Institut, Experimentelle Physik VII, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany

We investigated the valence band of the Bi/Ag(111) surface alloy by means of spin- and angle-resolved photoelectron spectroscopy (SARPES), with variable photon energy and light polarization. The sample growth and all measurements were performed in ultrahigh vacuum conditions. We obtained ARPES-spectra at room temperature, for photon energies between 20 and 30 eV, with s- and p-polarized light. The spin-splitted Rashba-type sp_z and p_xp_y surface states [1,2] were observed near Fermi level and exhibit strong intensity variations with the incident light polarization, due to the dipole selection rules. Spin-resolved energy distribution curves were measured at particular points of the surface Brillouin zone, for different photon energies and light polarizations. The surface states are strongly spin-polarized, reaching up to 80% spin-polarization. We show that the spin-polarization has a complex dependence on the parallel momentum, the photon energy and the orbital character of the states. We discuss our results in sight of the peculiar entanglement between the spin and the momentum of the electrons in the Rashba-type surface states [1,2].

[1] H. Bentmann et al., Phys. Rev. Lett. 108, 196801 (2012).

[2] S. N. P. Wissing et al., Phys. Rev. Lett. 113, 116402 (2014)