Berlin 2005 – scientific programme

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SYFS: Nichtflüchtige Festkörperspeicher

SYFS 2: Ferroelectric and dielectric memories

SYFS 2.2: Talk

Saturday, March 5, 2005, 15:15–15:30, TU HE101

First-principles theory of interfacial electronic structures and energy barriers in electroceramic thin-film devices — •Christian Elsässer¹, Matous Mrovec¹, Jan-Michael Albina¹, and Bernd Meyer² — ¹Fraunhofer-Institut für Werkstoffmechanik IWM, Wöhlerstr. 11, 79108 Freiburg — ²Lehrstuhl für Theoretische Chemie, Ruhr-Universität, Universitätsstr. 150, 44780 Bochum

Nanostructured thin-film devices on the basis of electroceramic perovskite-type oxides have very promising structural, physical and chemical properties for highly integrated functional components, e.g., in computer technology, like high-density dynamic random access memory (RAM) made of (Ba,Sr)TiO₃, or novel non-volatile ferroelectric Pb(Zr,Ti)O₃ RAM devices. Critical issues in such systems are the interfacial structure, adhesion and electrical barriers at the contacts of the electroceramic thin films to conducting electrodes (e.g., Pt, SrRuO₃), and to insulating substrates (e.g., SrTiO₃, LaAlO₃).

First-principles electronic-structure calculations, by density functional theory and the mixed-basis pseudopotential method, were carried out to analyse interfacial Schottky barriers and band offsets at planar and coherent perovskite/metal and perovskite/perovskite contacts. Influences of different electrode materials, varying chemical film compositions and interface terminations on the interfacial energy barriers will be discussed.

This work is supported by the German Research Foundation (DFG) within the Priority Program "Integrated electroceramic functional structures".