Regensburg 2013 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 15: Poster Session
MM 15.5: Poster
Montag, 11. März 2013, 18:00–20:00, Poster E
Cation -Anion interactions, Noncentrosymmetry vs Centrosymmetry : A first-principles study — •Abhishek Kumar Mishra1, Kenneth V. Poeppelmeier2, and Umesh V. Waghmare1 — 1Theoretical Sciences Unit, J Nehru Centre for Advanced Scientific Research, Bangalore-560064, INDIA — 2Departments of Chemistry, Northwestern University, Evanston, Illinois, 60208-3113
Materials with non-centrosymmetric (NC) structure posses different technologically important physical properties such as piezoelectricity, ferroelectricty and pyroelectricity due to their symmetry dependent properties. These properties make them find applications in different fields viz. burglar alarms, pollution monitors, thermal detectors, multifunctional devices, photonics technology. Several interesting inter-relationships occur between the symmetry-dependent properties and that is why these materials are of special interest in materials chemistry.
We present a theoretical study of structure-property correlation in noncentrosymmetric KNaNbOF5 and centrosymmetric CsNaNbOF5, based on first principles calculations followed by subsequent comparison with experiments. We have worked on stability, electronic and polar properties of these structures and on their solid solutions. Electronic density of states calculations reveals specific bands responsible for breaking of centrosymmetry in these structures. Using Berry phase method we have calculated values of polarization and also reported electronic dielectric constant values.