Dresden 2017 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 96: Metallic Nanowires on Semiconductor Surfaces
O 96.9: Vortrag
Donnerstag, 23. März 2017, 17:00–17:15, WIL C107
Strain induced quasi-one dimensional structure of rare earth silicides on Si substrates — Frederic Timmer1, Robert Oelke1, Christof Dues2, Simone Sanna2, Wolf Gero Schmidt2, Martin Franz3, Stephan Appelfeller3, Mario Dähne3, and •Joachim Wollschläger1 — 1Fachbereich Physik, Universität Osnabrück, Germany — 2Lehrstuhl für Theoretische Physik, Universität Paderborn, Germany — 3Institut für Festkörperphysik, Technische Universität Berlin, Germany
One dimensional (1D) systems have attracted a lot of attention since their physical properties are distinctively different from structures of higher dimensionality. Recently, a new class of quasi-1D systems based on rare earth silicides has attracted attention. Here, we report on combined studies on quasi-1D structures by scanning tunneling microscopy (STM), spot profile analysis of low-energy electron diffraction (SPA-LEED) and density functional theory (DFT).
Depositing rare earth elements as Dy or Tb at elevated temperature on Si(111), a 2√3×√3 superstructure is observed. This structure is attributed to the formation of periodically arranged Si vacancies in different silicide layers. The complex structure of this superstructure with buckled surface layer, √3×√3 superstructure in the first subsurface layer 2√3×√3 superstructure in the second subsurface layer can only be analyzed applying the different techniques used here. The anisotropic character of this structure is emphasized by the formation of periodically arranged domain boundaries. The width of the silicide domains formed in two domains is roughly two unit cells.