Berlin 2012 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 24: Joint Session "Soft X-ray Resonant Scattering for Complex Structural and Magnetic Investigations" (jointly with KR), Organization: Eberhard Goering (MPI-IS Stuttgart)

MA 24.2: Topical Talk

Mittwoch, 28. März 2012, 10:00–10:30, BH 243

Orbital reflectometry of nickelate heterostructures — •Eva Benckiser — Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, Germany

The occupation of d-orbitals has a key influence on the physical properties of transition metal oxides. Heterostructures of these oxides offer the possibility to control the orbital occupations because the electronic structure is very sensitive to changes in the transition-metal-oxygen bond distances induced by strain, dimensional constrains, and the chemical bonding to ions with different electronic configuration. However, atomic-scale modulations of the orbital occupation could thus far not be probed in a quantitative manner. We present results from a polarized soft x-ray resonant reflectivity study on superlattices composed of metallic LaNiO₃ and insulating LaAlO₃, LaGaO₃, or DyScO₃. We will demonstrate that it is possible to derive quantitative, spatially resolved orbital polarization profiles with differences of ∼ 3% in the occupation of Ni e_g orbitals in adjacent atomic layers and discuss these results in context with recent theoretical predictions.¹⁻³ The possibility to quantitatively correlate theory and experiment on the atomic scale opens up new perspectives for orbital physics in oxide heterostructures. ¹ Chaloupka, J. and Khaliullin, G., Phys. Rev. Lett. 100, 016404 (2008). ² Hansmann, P. et al., Phys. Rev. Lett. 103, 016401 (2009) and arXiv:1111.1111 ³ Han, M. J., Marianetti, C. A. & Millis, A. J. Phys. Rev. B 82, 134408 (2010)