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DF: Dielektrische Festkörper

DF 10: Elektrische, elektromechanische und optische Eigenschaften

DF 10.4: Vortrag

Dienstag, 8. März 2005, 15:00–15:20, TU EMH225

Electrical, optical, and electrooptical properties of BaTiO₃/SrTiO₃ superlattices with symmetric and asymmetric structures — •Hassan Chaib, Lukas Eng, and Tobias Otto — Institute of Applied Photophysics, University of Technology Dresden, D-01062 Dresden, Germany

The electrical, optical, and electrooptical properties of BaTiO₃/SrTiO₃ superlattices are theoretically investigated using a microscopic quantum mechanical model based on the orbital approximation in correlation with the dipole-dipole interaction. First-, second-, and third-order electronic polarizabilities of the constituent ions have been considered in this calculation in order to obtain accurate results for both the dielectric spontaneous polarization, the relative dielectric constant, the refractive indices, and the linear electrooptic coefficients of the BaTiO₃/SrTiO₃ superlattices with symmetric (n=m) and asymmetric (n≠ m) structures ("n/m" represents the stacking periodicity of n unit cells for BaTiO₃/m unit cells for SrTiO₃). The present calculation shows that the BaTiO₃-rich structures (n>m) possess the largest values of the spontaneous polarization, optical birefringence, and linear electrooptic coefficients while the SrTiO₃-rich structures (n<m) show the largest values of the relative dielectric constant.