Dresden 2014 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 81: Oxide and Insulator Surfaces III
O 81.7: Vortrag
Donnerstag, 3. April 2014, 17:30–17:45, PHY C 213
Surface phonons of titanium oxide ultrathin films on Pt(100) — •Florian Schumann1, Klaus Meinel1, Johannes Lotze1, and Wolf Widdra1,2 — 1Institute of Physics, Martin-Luther-Universität Halle-Wittenberg, Halle, Germany — 2Max-Planck Institut für Mikrostrukturphysik, Halle, Germany
Phonons and their softening are key elements for the understanding of the long-range coupling in ferroelectric and multiferroic materials. Titanium oxide is a relevant part and one possible termination in many perovskites like BaTiO3 and SrTiO3. In thin films, structure and lattice dynamics can be modified due to the interaction at the interfaces. Here we study the surface phonons of ultrathin titanium oxides grown by MBE on Pt(100). Three different well-ordered TiOx phases have been identified as (4×13), (3×5) and (2√2×2√2)R45∘ structures based on their LEED pattern [1,2]. The three phases can be distinguished by their charakteristic phonon frequencies at 1020, 755 and 625 cm−1, respectively. The stability of the three phases as function of termperature and oxygen pressure will be discussed based on the phonon spectroscopy.
[1] T. Matsumoto et al., Surf. Sci. 572: 127, 2004.
[2] T. Matsumoto et al., Surf. Sci. 572: 146, 2004.