Berlin 2012 – scientific programme

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DF: Fachverband Dielektrische Festkörper

DF 13: Poster II

DF 13.28: Poster

Wednesday, March 28, 2012, 15:00–17:30, Poster E

Lithium tantalate electronic and optical properties calculated from first principles — •Arthur Riefer, Simone Sanna, and Wolf Gero Schmidt — Theoretische Physik, Universität Paderborn, 33095 Paderborn, Germany

Ferroelectric materials like Lithium tantalate (LT) are very important for the fabrication of non-linear optical and electro-optical devices. Despite its huge range of applications first principles studies including many-body interactions in the electronic structure and optical spectra of ferroelectrics are rare[2,3]. In particular for LT we are not aware of calculations going beyond density functional theory (DFT). In order to contribute to a better understanding of the LT electronic and optical properties we calculate its quasiparticle band structure within the GW approximation for the electronic self-energy. The optical response is calculated from a Bethe-Salpeter-type approach, thus including excitonic and local-field effects from first principles. The results are compared to similar calculations for other ferroelectric materials like Lithium niobate (LN). Also we present spectra for composite materials consisting of both LN and LT.

[1] Y. Xu, Ferroelectric materials and their applications, North-Holland, 1991

[2] W. G. Schmidt et al., Phys. Rev. B 77, 035106 (2008)

[3] C. Thierfelder et al., phys. stat. sol. (c) 7, 362 (2010)