Regensburg 2016 – scientific programme
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O: Fachverband Oberflächenphysik
O 47: Electronic Structure of Surfaces: Spectroscopy, Surface States
O 47.11: Poster
Tuesday, March 8, 2016, 18:15–20:30, Poster E
Spin-orbit interaction in Pb monolayers on Si(111) — •Christian Brand1, Haiyue Liu1, Philipp Kröger1, Herbert Pfnür1, Gabriel Landolt2,3, Jan-Hugo Dil2,4, Stefan Muff2,4, Michael C. Tringides5, and Christoph Tegenkamp1 — 1Leibniz Universität Hannover, Germany — 2Swiss Light Source, Villigen, Switzerland — 3Universität Zürich, Switzerland — 4École Polytechnique Fédérale de Lausanne, Switzerland — 5Ames Laboratory & Iowa State University, Ames, USA
Atomic monolayers (ML) of Pb/Si(111) have recently been found to be superconducting below TC ≈ 1.6 K, but the mechanism behind the evolution of these 2d states is yet not understood. In the range from 6/5 ML to 4/3 ML supercells consisting of linear combinations of √7 × √3 and √3 × √3 unit cells are formed (so-called Devil’s staircase regime). This allows us to the tune spin-orbit interaction (SOI), the electronic and atomic structure via adsorption of minute amounts of Pb. In this study we present (SR)-ARPES, DC-, and magneto-transport measurements at low T (> TC) to evaluate the influence of SOI on the Pb surface states. As derived from magneto-transport weak-antilocaization occurs indicating strong SOI, while Hall resistance slopes shows pure n-type conductivity. The carrier concentrations agree well with EDCs from ARPES, while SR-MDCs reveal a complex spin-texture at EF in Pb surface states around the surface high symmetry points. Moreover, Pb induced high Schottky barriers at highly n-doped substrates reveal new insights into hybridization of Si bulk states in valence band by confinement effects near the surface.