Berlin 2012 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 31: Clean surfaces II
O 31.10: Vortrag
Dienstag, 27. März 2012, 12:45–13:00, A 060
Imaging and manipulation of ferroelectric domains by STM and STS — •Maik Christl1, Stefan Förster1, Hannes Bayer1, and Wolf Widdra1,2 — 1Institute of Physics, Martin-Luther-Universität Halle-Wittenberg, Halle, Germany — 2Max Planck Institute of Microstructure Physics, Halle, Germany
Piezoresponse force microscopy (PFM) has emerged as a basic tool for imaging and domain engineering on ferroelectric materials, however the lateral resolution is limited down to several nanometers [1].
Here we present an alternative approach of characterizing ferroelectric domain structures by using the scanning tunneling microscope (STM). Epitaxial BaTiO3 films of various thickness which have been grown under ultra high vacuum conditions on a Pt(100) substrate [2] have been studied by STM and STS at room temperature. DI/dV maps allow to identify the out-of-plane domain structure in the BaTiO3 films as prepared. Upon applying higher STM bias voltages, the ferroelectric polarization can be reversed and domain structures will be written. With STS a clear contrast between positively and negatively poled areas becomes visible. Additionally, downward polarized areas appear higher in the STM topography. The manipulated areas are stable for days.
All STM data will be compared with PFM measurements of the same sample.
[1] M. Alexe and A. Gruverman, Nanoscale Characterisation of Ferroelectric Materials, Springer, Berlin Heidelberg 2004.
[2] S. Förster, M. Huth, K.-M. Schindler, and W. Widdra, J. Chem. Phys. 135, 104701 2011.