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In this talk I will review our recent results in theoretical modeling and experimental realization of several epitaxial oxide heterostructures. I will set the stage with a brief discussion of the n-type conductive SrTiO3/LaA1O3 interface . The origin of charge in this nominally insulating system is still under intense debate, and the difficulties are, in my opinion, generic to the entire field. Our theoretical results are consistent with the originally proposed polar catastrophe model, should the field be indeed stabilized in polar LaA1O3. However, our results indicate that this may be difficult to achieve. I then will discuss extrinsic magnetoelectric coupling at the interface of a perovskite ferroelectric and conventional ferromagnet [2,3]. In contrast with the previously proposed models, the structure we consider offers the robust, linear coupling. If time permits, I will describe our efforts to achieve the monolithic integration of ferromagnetic oxide LaCoO3(LCO) and silicon for possible applications in spintronics . The integration is achieved via the single crystal SrTiO3 (STO) buffer epitaxially grown on Si. The intermediate spin state is stabilized by epitaxial strain at the STO/LCO interface.
1. J. K. Lee and A. A. Demkov, Phys. Rev. B 78, 193104 (2008).
2. T. Cai, Q. Niu, J. K. Lee, Na Sai, and A. A. Demkov, Phys. Rev. B 80, 140415(R) (2009).
3. J. K. Lee, Na Sai, T. Cai, Q. Niu and A. A. Demkov, Phys. Rev. B 81, 144425 (2010).
4. A. Posadas, M. Berg, H. Seo, D. J. Smith, H. Celio, A. P. Kirk, D. Zhernokletov, R. M. Wallace, A. de Lozanne, and A. A. Demkov, Appl. Phys. Lett. 98, 055104 (2011).