Soft-mode spectroscopy of epitaxial BaTiO.sub.3./sub./SrTiO.sub.3./sub. superlattices

0353086 - FZÚ 2011 RIV US eng J - Journal Article
Hlinka, Jiří - Železný, Vladimír - Nakhmanson, S.M. - Soukiassian, A. - Xi, X.X. - Schlom, D. G.
Soft-mode spectroscopy of epitaxial BaTiO₃/SrTiO₃ superlattices.
Physical Review. B. Roč. 82, č. 22 (2010), 224102/1-224102/5. ISSN 1098-0121
R&D Projects: GA MŠMT ME08109; GA ČR GA202/07/0591
Institutional research plan: CEZ:AV0Z10100520
Keywords : superlattice * perovskites * think films * ferroelecricity * phonon * spectroscopy
Subject RIV: BM - Solid Matter Physics ; Magnetism
Impact factor: 3.772, year: 2010

It is demonstrated that soft modes in 240 nm thick BaTiO3/SrTiO3 ferroelectric superlattices can be probed by infrared reflectivity measurements, which allows us to estimate the intrinsic in-plane dielectric constants of such thin superlattice slabs. Our analysis of the experimental results is combined with the first-principles based theoretical evaluation of optical polar modes in a model system representing the 60-atom periodic superlattice unit cell. This hybrid approach suggests that the observed soft mode is associated with a Slater-type polar mode confined mostly in the SrTiO3 component layer.
Permanent Link: http://hdl.handle.net/11104/0192428