Berlin 2018 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 67: Electronic structure of surfaces: Spectroscopy, surface states III
O 67.8: Vortrag
Mittwoch, 14. März 2018, 17:15–17:30, MA 042
Giant Rashba Splitting in Cu2Te and Ag2Te Surface Alloys — •Maximilian Ünzelmann1, Hendrik Bentmann1, Dean Nestorov1, Philipp Eck2, Domenico Di Sante2, Giorgio Sangiovanni2, Philipp Rosenzweig3, Sebastian Otto3, Thomas Fauster3, and Friedrich Reinert1 — 1Experimentelle Physik 7, Universität Würzburg — 2Theoretische Physik 1, Universität Würzburg — 3Lst. f. Festkörperphysik, Universität Erlangen-Nürnberg
By deposition of a 1/3 ML of Tellurium on M(111) surfaces (M=Cu,Ag) a (√3×√3)-R30∘ superstructure in M2Te stoichiometry is formed whereby every third M-atom is replaced by a Te-atom. This type of substitutional surface alloys is very well known as a model system for large Rashba-type spin-orbit splittings.
We investigated the surface band structure of M2Te/M(111) by means of one- and two-photon photoelectron spectroscopy and compare our photoemission data to density functional theory (DFT) band structure calculations.
For both substrates two fully occupied hole-like bands are found. We assign these to Te induced spz- and pxpy-states. Our ARPES data shows strong indications for a Rashba-type spin splitting with a Rashba parameter of about 2 eVÅ for the Ag2Te spz-state. Interestingly this value is much larger than that for Sb which has a similar atomic SOC. This manifests the influence of the atomic structure on the Rashba spin splitting.
Besides a series of image-potential-resonances 2PPE shows Te-induced unoccupied states in good agreement with DFT calculations.