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First principles investigation of polarisation at interfaces in multilayered strontium titanate

: Benedek, N.A.; Elsässer, C.; Finnis, M.W.


Finnis, M.W. ; European Materials Research Society -EMRS-:
Interfacial nanostructures in ceramics. A multiscale approach : Papers presented in Symposium J at the European Materials Research Society Spring Meeting, 28 May - 1 June, 2007
Bristol: IOP Publishing, 2008 (Journal of physics. Conference series 94.2008)
ISSN: 1742-6588
Art. 012005, 12 pp.
Symposium J "Interfacial Nanostructures in Ceramics - A Multiscale Approach" <2007, Strasbourg>
European Materials Research Society (Spring Meeting) <2007, Strasbourg>
Conference Paper, Journal Article
Fraunhofer IWM ()

One of the main factors which affects the bulk properties of multilayered perovskites is the atomic structure at the interface between different types of layers. We have applied Density Functional Perturbation Theory to investigate the polarisation properties of interfaces in two different phases of nonstoichiometric SrTiO3, the Ruddlesden-Poppper and Magnéli phases. Our calculated Born effective charge tensors and high-frequency dielectric constants are compared for each type of interface and bulk SrTiO 3. For both phases, we find that the presence of the interface introduces huge anisotropy into the Born effective charges of the participating ions. We attempt to interpret our results using a simplified tight binding model and analyse the limitations of such an approach.