Dresden 2017 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 31: Oxide and Insulator Surfaces: Structure, Epitaxy and Growth I
O 31.7: Vortrag
Dienstag, 21. März 2017, 12:00–12:15, WIL C107
Surface lattice vibrations of BaO(001) thin film on Pt(001) — •Veronica Goian1, Florian Schumann1, and Wolf Widdra1,2 — 1Institute of Physics, Martin-Luther-Universität Halle-Wittenberg, 06120 Halle, Germany — 2Max-Planck-Institut für Mikrostrukturphysik, 06120 Halle, Germany
In this work, we report the growth of c(2x2) ordered BaO(001) thin films on Pt(001). The thicknesses of the thin films vary from 36 monolayers down to 3 monolayers. The stoichiometry and long range order are analyzed by AES and LEED. According to LEED, BaO thick films start to order near 1075 K. The surface vibrational properties were measured near the surface Brillouin zone center using high-resolution electron energy loss spectroscopy (HREELS). The Fuchs-Kliewer phonon for thick films appears at 390 cm−1 and becomes stronger at higher UHV annealing temperatures. A quantitative comparison of the experimental data with the calculated loss function based on dielectric theory reveals an excellent agreement between bulk and BaO thin film phonon properties. Temperature and thickness dependence of HREELS spectra will be discussed.