Dresden 2017 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 43: Topological Insulators I (jointly with DS, HL, O, TT)
MA 43.9: Vortrag
Mittwoch, 22. März 2017, 17:15–17:30, HSZ 401
Instability of the topologically protected surface state in Bi2Se3 upon deposition of gold — •Andrey Polyakov1, Holger L. Meyerheim1, Christian Tusche2, Daryl E. Crozier3, and Arthur Ernst1 — 1Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany — 2Peter Grünberg Institut (PGI-6), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany, Germany — 3Department of Physics, Simon Fraser University Burnaby, BC Canada, V5A 1S6
We present an experimental and theoretical analysis of the stability of the Topological surface state (TSS) in Bi2Se3 upon sub-monolayer deposition of Au. Extended x-ray absorption fine structure experiments provide clear evidence that Au -when deposited on the (0001) surface kept at 160 K- substitutes Bi atoms within the first quintuple layer. This goes in parallel with the dramatic weakening of the spectral density of the TSS as observed by angular resolved photoemission. In accordance with first-principles calculations, Au in Bi substitutional sites within the first QL creates a d-type resonant state near EF, which hybridizes with the TI bands and substantially modifies its surface electronic structure. According to the model of Black-Schaffer et al. [1] a bulk-surface interaction is a prerequisite for the gap opening, since the TSS is not protected by scattering processes involving bulk three-dimensional states. References: [1] A. M. Black-Schaffer and A. V. Balatsky, Phys. Rev. B 86, 115433 (2012). Acknowledgements: Work supported by SPP 1666. Work at the APS is supported by the U.S. DOE under Contract No. DE-AC02-06CH11357.