Dresden 2014 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 16: Electronic Structure and Spin-Orbit Interaction II
O 16.5: Vortrag
Montag, 31. März 2014, 17:00–17:15, GER 38
A combined LEEM/PEEM study on ferroelectric domains in perovskite crystals — •Hatice Doğanay1, Ingo Krug1, Daniel Gottlob1,2, Stefan Cramm1, and Claus M. Schneider1,2 — 1Peter Grünberg Institut (PGI-6), Forschungszentrum Jülich — 2Fakultät für Physik, Universität Duisburg Essen
We investigated the local electronic structure in domains of BaTiO3(001), which is considered a model perovskite-type ferroelectric oxide with potential for technological applications [1] due to its large dielectric permittivity, spontaneous polarization, piezoelectricity, and nonlinear optical responses. Polarized x-rays and variable photon energy enables photoelectron microscopy (PEEM)with element selective contrast and nanospectroscopy of the electronic structure differences between the ferroelectric domains. AES and LEED show that the surface is BaO terminated with a (2x2) reconstruction. For a clean surface the MEM-LEEM transition shift between different ferroelectric domains was 300 mV. Such a significant value is related to opposite polarizations perpendicular to the surface, pointing either outwards (P+) or inwards (P-). Equally important, in order to study the charge anisotropy with spatial resolution, XAS measurements have been performed. Accordingly, we were able to image the ferroelectric domains with the help of performed and calculated XLD Spectra, recorded at our UE56/1-SGM beamline (BESSY-II, Berlin) with an aberration-corrected LEEM/PEEM. [1] Shimizu et al. J. Phys.: Condens. Matter 25 (2013) 132001