title: Spin texture of Bi2Se3 thin films in the quantum tunneling limit.
abstract: By means of spin- and angle-resolved photoelectron spectroscopy we studied the spin structure of thin films of the topological insulator Bi2Se3 grown on InP(111). For thicknesses below six quintuple layers the spin-polarized metallic topological surface states interact with each other via quantum tunneling and a gap opens. Our measurements show that the resulting surface states can be described by massive Dirac cones which are split in a Rashba-like manner due to the substrate induced inversion asymmetry. The inner and the outer Rashba branches have distinct localization in the top and the bottom part of the film, whereas the band apices are delocalized throughout the entire film. Supported by calculations, our observations help in the understanding of the evolution of the surface states at the topological phase transition and provide the groundwork for the realization of two-dimensional spintronic devices based on topological semiconductors.
authors.affiliation: Physik-Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland and Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen, Switzerland.
authors.forename: Gabriel
authors.initials: G
authors.lastname: Landolt
authors.affiliation: Physikalisches Institut, Experimentelle Physik III, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany.
authors.forename: Steffen
authors.initials: S
authors.lastname: Schreyeck
authors.affiliation: Institute of Strength Physics and Materials Science, Russian Academy of Sciences, Siberian Branch, Akademicheskiy prospekt 2/4, Tomsk, 634021 Russia and Tomsk State University, Tomsk, 634050 Russia.
authors.forename: Sergey V
authors.initials: SV
authors.lastname: Eremeev
authors.affiliation: Physik-Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland and Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen, Switzerland.
authors.forename: Bartosz
authors.initials: B
authors.lastname: Slomski
authors.affiliation: Physik-Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland and Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen, Switzerland and Institut de Physique de la Matière Condensée, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.
authors.forename: Stefan
authors.initials: S
authors.lastname: Muff
authors.affiliation: Physik-Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland.
authors.forename: Jürg
authors.initials: J
authors.lastname: Osterwalder
authors.affiliation: Tomsk State University, Tomsk, 634050 Russia and Donostia International Physics Center (DIPC) and CFM-MPC, Centro Mixto CSIC-UPV/EHU, Departamento de Física de Materiales, UPV/EHU, 20080 San Sebastián, Spain.
authors.forename: Evgueni V
authors.initials: EV
authors.lastname: Chulkov
authors.affiliation: Physikalisches Institut, Experimentelle Physik III, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany.
authors.forename: Charles
authors.initials: C
authors.lastname: Gould
authors.affiliation: Physikalisches Institut, Experimentelle Physik III, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany and Institute of Physics, Polish Academy of Sciences, aleja Lotników 32/46, 02-668 Warsaw, Poland.
authors.forename: Grzegorz
authors.initials: G
authors.lastname: Karczewski
authors.affiliation: Physikalisches Institut, Experimentelle Physik III, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany.
authors.forename: Karl
authors.initials: K
authors.lastname: Brunner
authors.affiliation: Physikalisches Institut, Experimentelle Physik III, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany.
authors.forename: Hartmut
authors.initials: H
authors.lastname: Buhmann
authors.affiliation: Physikalisches Institut, Experimentelle Physik III, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany.
authors.forename: Laurens W
authors.initials: LW
authors.lastname: Molenkamp
authors.affiliation: Physik-Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland and Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen, Switzerland and Institut de Physique de la Matière Condensée, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.
authors.forename: J Hugo
authors.initials: JH
authors.lastname: Dil