Berlin 2018 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 18: Focus Session: Frontiers in Reducible Oxide Surface Science II

O 18.10: Vortrag

Montag, 12. März 2018, 18:00–18:15, HE 101

In-situ studies of the reduction of ultrathin BaTiO₃ on Pt(111) — •Jonas Pantzer¹, Stefan Förster¹, Jan Ingo Flege², Jens Falta², and Wolf Widdra^1,3 — ¹Martin-Luther-Universität Halle-Wittenberg, 06120 Halle, Germany — ²Universität Bremen, 28359 Bremen, Germany — ³Max-Planck-Institute for Microstructure Physics, 06120 Halle, Germany

Reduced ultrathin films derived from the prototypical perovskite oxides BaTiO₃ and SrTiO₃ have recently attracted attention due to the their transformation into two-dimensional oxide quasicrystals (OQCs) on a hexagonal metal support [1]. For BaTiO_x on Pt(111), the OQC formation proceeds in two steps via an amorphous two-dimensional wetting layer[2].

Here we report on in-situ low energy electron microscopy (LEEM) studies of morphological changes starting from stoichiometric BaTiO₃(111) islands on Pt(111). At 1350 K the genesis and movement of a diffusion front of an amorphous two-dimensional wetting layer on the bare platinum is observed, which starts at the BaTiO₃(111)-islands. Subsequently, a second, much slower, diffusion front is observed at the edges of the BaTiO₃(111)-islands, indicating a crystallisation of the wetting layer into differently oriented BaTiO₃(111).

[1] Förster et al., Nature 502, 215 (2013)

[2] Förster et al. Ann. Phys. 529, 1600250 (2017)