Dresden 2014 – scientific programme

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SYOM: Symposium One-dimensional Metals: Reality or Fiction

SYOM 2: Posters: One-Dimensional Metals: Reality or Fiction (jointly organized by DS, HL, O, TT)

SYOM 2.8: Poster

Thursday, April 3, 2014, 16:00–19:00, P1

Dimensionality and Metallicity of quasi-1D Ag:Si(557) Investigated by Angle-Resolved Photoemission — •Chris Nicholson¹, Claude Monney¹, Ulrich Krieg², Michele Puppin¹, Yunpei Deng¹, Christoph Tegenkamp², Herbert Pfnür², Karsten Horn¹, Ralph Ernstorpher¹, and Martin Wolf¹ — ¹Fritz-Haber-Institut of the Max Planck Society, Berlin, Germany — ²Leibniz Universität, Hannover, Germany

Self-assembled quasi-one-dimensional (1D) atomic wires on semiconductor surfaces show a range of interesting physical phenomena, and are promising for nanoscale devices. However, the number of metallic systems available is relatively small. Angle-Resolved Photoemission Spectroscopy (ARPES) is a powerful tool that can directly address the metallicity of these systems, and can additionally connect macroscopic conductivity to specific parts of the electronic band structure. We apply ARPES to Ag:Si(557): around 1ML coverage, plasmonic losses with a 1D dispersion have been observed at room temperature in Electron Energy Loss Spectra (EELS), in contrast to insulating behaviour observed with EELS and ARPES at lower Ag coverage. Preparation has been optimised by LEED and ARPES measurements with He I, while high resolution ARPES near the Fermi level allows us to search for metallic surface states and measure their dispersion, in order to assess their relation to the low-dimensional plasmonic excitations. Furthermore, we have developed a new high-repetition rate VUV light source for ultrafast time-resolved ARPES measurements, which will provide complementary dynamic information on such quasi-1D systems.