Dresden 2014 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 81: Oxide and Insulator Surfaces III
O 81.10: Vortrag
Donnerstag, 3. April 2014, 18:15–18:30, PHY C 213
In-situ characterization of ferroelectric domains of epitaxially BaTiO3(100) ultrathin films on Pt(100) by STM and STS — •Maik Christl1, Klaus Meinel1, Stefan Förster1, and Wolf Widdra1,2 — 1Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, Halle, Germany — 2Max-Planck-Institut für Mikrostrukturphysik, Halle, Germany
The understanding of ferroelectric domain properties of ultrathin films is of fundamental interest with regard to interface effects and smallest domain dimensions [1]. To adress these issues the widely used piezoresponse force microscopy is not a suitable tool due to its limited resolution and the low mechanical stability of the ultrathin films.
Alternatively, we apply scanning tunneling microscopy (STM) and spectroscopy (STS) for writing and reading of ferroelectric domains in BaTiO3(100) thin films. The films were grown pseudomorphically on a Pt(100) substrate with compressive strain of 2% [2]. A voltage dependent contrast between positively and negatively poled areas appears in dI/dV maps. In particular a contrast inversion at 1 V between different domains is observed. This inversion results from a characteristic shift of the density of states between c+ and c− domains as confirmed by dI/dV point spectra. For ultrathin films of 2 and 3 unit cell thickness, we find different ferroelectric switching behaviors.
[1] J. F. Scott, J. Phys.: Condens. Matter 18, 2006
[2] S. Förster et al., J. Chem. Phys. 135, 104701 2011