Growth of nanoscale BaTiO 3 /SrTiO 3 superlattices by molecular-beam epitaxy

• Published in: Journal of materials research 2008-05, Vol.23 (5), p.1417-1432
• Main Authors: Soukiassian, A., Tian, W., Vaithyanathan, V., Haeni, J.H., Chen, L.Q., Xi, X.X., Schlom, D.G., Tenne, D.A., Sun, H.P., Pan, X.Q., Choi, K.J., Eom, C.B., Li, Y.L., Jia, Q.X., Constantin, C., Feenstra, R.M., Bernhagen, M., Reiche, P., Uecker, R.
• Format: Article
• Language: English
• ISSN: 0884-2914; 2044-5326
• DOI: 10.1557/JMR.2008.0181

Commensurate BaTiO 3 /SrTiO 3 superlattices were grown by reactive molecular-beam epitaxy on four different substrates: TiO 2 -terminated (001) SrTiO 3 , (101) DyScO 3 , (101) GdScO 3 , and (101) SmScO 3 . With the aid of reflection high-energy electron diffraction (RHEED), precise single-monolayer doses of BaO, SrO, and TiO 2 were deposited sequentially to create commensurate BaTiO 3 /SrTiO 3 superlattices with a variety of periodicities. X-ray diffraction (XRD) measurements exhibit clear superlattice peaks at the expected positions. The rocking curve full width half-maximum of the superlattices was as narrow as 7 arc s (0.002°). High-resolution transmission electron microscopy reveals nearly atomically abrupt interfaces. Temperature-dependent ultraviolet Raman and XRD were used to reveal the paraelectric-to-ferroelectric transition temperature ( T C ). Our results demonstrate the importance of finite size and strain effects on the T C of BaTiO 3 /SrTiO 3 superlattices. In addition to probing finite size and strain effects, these heterostructures may be relevant for novel phonon devices, including mirrors, filters, and cavities for coherent phonon generation and control.