Dresden 2017 – scientific programme

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O: Fachverband Oberflächenphysik

O 79: Electronic Structure of Surfaces: Spectroscopy, Surface States I

O 79.4: Talk

Wednesday, March 22, 2017, 16:00–16:15, WIL C307

Spin-dependence in photoemission from strongly spin-orbit coupled systems — •Henriette Maaß¹, Hendrik Bentmann¹, Eugene E. Krasovskii^2,3,4, Thiago R. F. Peixoto¹, Christoph Seibel¹, and Friedrich Reinert¹ — ¹Experimentelle Physik VII, Universität Würzburg, D-97074 Würzburg — ²Departamento de Física de Materiales, Universidad del Pais Vasco UPV/EHU, 20080 San Sebastían/Donostia, Spain — ³Donostia International Physics Center (DIPC), 20018 San Sebastían/Donostia, Spain — ⁴IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Spain

Strong spin-orbit coupling governs the emergence of electronic states with an intrinsic spin polarization. Prominent examples are topological surface states which form for example on the surface of Bi₂Te₃, or Rashba-type spin-splittings in noble metals and surface alloys. Using spin- and angle resolved photoelectron spectroscopy we have investigated the spin- and orbital texture of the topological insulators Bi₂Te₃ and Bi₂Te₂Se as well as the surface alloy BiAg₂. Interestingly, whereas at first sight the measured photoelectron spin polarization strongly resembles the one expected for the ground state, strong modulations occur in both, the topological surface states as well as Rashba-type surface states, when the light polarization or photon energy is changed. These modulations reflect a strong influence of the symmetry of initial and final state as well as the experimental alignment on the measured photoelectron spin polarization. Our data yields insight into the relation between the result of a spin-sensitive photoemission experiment and the intrinsic spin-structure of material.