Dresden 2009 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 17: Oxides and insulators III

O 17.10: Vortrag

Dienstag, 24. März 2009, 12:45–13:00, SCH A01

Ferroelectric domain structures on BaTiO₃(100) observed by Laser-excited PEEM — •Anke Höfer, Klaus Duncker, Stefan Förster, and Wolf Widdra — Martin-Luther-Universität Halle-Wittenberg, Halle, Germany

The ferroelectric domain structure at a single crystal BaTiO₃(100) surface is imaged by photoelectron emission microscopy (PEEM) using a fully tunable femtosecond laser source. For a BaTiO₃(100) surface which is prepared under UHV conditions by sputtering and annealing in an oxygen atmosphere, at room temperature a stripe like domain pattern is observed with high contrast aligned in the high symmetry [100] direction of the substrate. The PEEM pattern is explained by sequences of 90^∘-a-c domains.

Wavelength-dependent images with UV excitation in the range of 290 - 330 nm show a varying domain contrast and allow the determination of the local photoemission threshold for one ferroelectric domain. For higher laser pulse energies and for wavelengths below the onset of one-photon photoemission, two-photon PEEM images show the ferroelectric domain structure as well.