Dresden 2014 – scientific programme

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MA: Fachverband Magnetismus

MA 19: Poster I

MA 19.49: Poster

Tuesday, April 1, 2014, 13:00–15:30, P1

Sb₂Te₃ ultrathin films on Si(111): magnetic surface doping and circular dichroism in angle-resolved photoemission spectroscopy — •M. Eschbach¹, M. Patt¹, L. Plucinski¹, V. Feyer¹, G. Mussler², D. Grützmacher², and C.M. Schneider¹ — ¹Peter Grünberg Institut PGI-6, FZ Jülich, Germany — ²Peter Grünberg Institut PGI-9, FZ Jülich, Germany

Three-dimensional topological insulators are novel states of quantum matter and are combining an insulating bulk energy gap with conducting Dirac-like states at the surface. These topological surface states (TSS) are due to strong spin-orbit coupling. They are topologically protected against back-scattering by time-reversal symmetry and exhibit a spin-polarized chiral structure. We study epitaxially grown thin films of intrinsically p-type doped Sb₂Te₃ by means of high-resolution angle- and spin-resolved photoemission spectroscopy. Bulk and surface doping with (non-) magnetic impurities and their influence on the electronic structure and spin polarization of the TSS are characterized in detail. Magnetic impurities should break the time-reversal symmetry which should lead to a bandgap opening close to the Fermi level i.e. a massive Dirac fermion state which should be visible in high-resolution ARPES. Furthermore, at our soft x-ray undulator beamline NanoESCA in ELETTRA/Trieste we perform circular dichroism experiments for different photon energies to indirectly probe the spin texture of the TSS. Subsequently, this data will be correlated to spin-polarized ARPES data measured using a recently developed highly efficient 2-dimensional spin-polarizing electron mirror.