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DF: Dielektrische Festkörper

DF 1: Internal Symposium “Integrated Electroceramic Functional Structures”

DF 1.2: Vortrag

Montag, 27. März 2006, 10:10–10:30, M{\"U}L Elch

Electronic structures and mechanical stabilities of coherent and semi-coherent perovskite interfaces from first-principles — •Christian Elsässer¹, Jan-Michael Albina¹, Matous Mrovec¹, and Bernd Meyer² — ¹Fraunhofer-Institut für Werkstoffmechanik, Freiburg, Germany — ²Ruhr-Universität Bochum, Bochum, Germany

Electroceramic thin-film heterostructures made of perovskite-type metal oxides are promising as alternatives to silicon-based components in microelectronics. The function and stability of such thin-film components are determined by the structure and chemistry of the few nm thin films and their contacts to substrates or electrodes. For the predictive development of electroceramic devices with desired functions, e.g., for dielectric or ferroelectric data storage, useful microscopic information about interfacial electronic structures and mechanical stabilities can be obtained from first-principles density functional theory. Calculations using the mixed-basis pseudopotential method were carried out for electronic energy barriers and mechanical separation energies of (001)-oriented interface models with SrTiO₃ in contact to three different perovskites: coherent SrTiO₃/LaAlO₃ with LaAlO₃ as an insulating substrate, coherent SrTiO₃/SrRuO₃ with SrRuO₃ as a conducting electrode, and semi-coherent SrTiO₃/SrZrO₃. For the latter system, with interfacial mismatch of 6%, a semi-coherent interface model with localized misfit dislocations separated by coherent regions was employed to estimate the influence of dislocation cores on electronic energy barriers and on mechanical separation energies.