Regensburg 2007 – wissenschaftliches Programm
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DF: Fachverband Dielektrische Festkörper
DF 7: Dielectric and Ferroelectric Thin Films and Nanostructures I
DF 7.4: Vortrag
Dienstag, 27. März 2007, 15:50–16:10, H11
Ferroelectric Thin Films used as Nonlinear Capacitors — •Kay Barz1, Martin Diestelhorst1, Horst Beige1, Ludwig Geske1,2, Marin Alexe2, and Dietrich Hesse2 — 1Institut für Physik, Martin-Luther-Universität Halle-Wittenberg — 2Max-Planck-Institut für Mikrostrukturphysik Halle
A simple serial resonance circuit with a ferroelectric bulk material used as capacitance can easily be driven into nonlinear regimes [1]. The response of such a circuit can be explained by the double well potential, introduced by the ferroelectric. Therefore the system can be described with 3 degrees of freedom, thus allowing it to pursue e.g. period doubling sequences into chaos. Recent experiences in ferroelectric thin films suggest, that even more degrees of freedom could be introduced by the semiconductor-like behaviour of ferroelectric thin film structures [2]. Hence, we deployed metal/ferroelectric/metal (MFM) and metal/ferroelectric/silicon (MFS) thin film structures as nonlinear capacitors in the resonance circuit. In the case of MFS, this led to the observation of a torus doubling bifurcation. As this phenomenon depends on the existence of a minimum set of 4 degrees of freedom it supports the previous made assumption. The talk will deal with the problem of separating nonlinear effects known from the pure ferroelectric (MFM and bulk, respectively) structures from those observable in ferroelectric/semiconductor heterostructures.
[1] Diestelhorst, et al. 1999 Int. J. of Bifurcation and Chaos 9, 243-250.
[2] Pintillie et al. 2005 Integrated Ferroelectrics 73, 37-48