Regensburg 2016 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 26: Poster session II
MM 26.3: Poster
Dienstag, 8. März 2016, 18:30–20:30, Poster B3
Investigation of perovskite interfaces with negative spherical aberration in HRTEM — •Tobias Meyer1, Patrick Peretzki1, Benedikt Ifland2, Christian Jooß2, and Michael Seibt1 — 1IV. Physical Institute, University Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany — 2Institute for Materials Science, University Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
The well-known Shockley-Queisser limit for the efficiency of single junction solar cells is based on energy losses due to transmission of low energy photons and thermalization of highly excited charge carriers. To overcome these limitations semi-conductors with small band gaps and long relaxation times are desirable. Long living states of small polarons have been observed in strongly correlated perovskite materials of the general form A1−xAx′BO3. The properties of these systems are related to orbital, charge and magnetic ordering phenomena which are highly dependent on the doping level and the particular choice of A, A′, and B. In the perfect perovskite lattice the B-site ion is centered in an octahedral spanned by the surrounding oxygen anions. Cooperative distortions and tilts of the octahedral affect the ordering phenomena and can also lead to relaxations of e.g. epitaxial strain. Junctions between Pr0.67Ca0.33MnO3 (PCMO) and SrTiO3 (STO) have been investigated in an image corrected TEM using negative spherical aberration imaging (NCSI) combined with focal series recording. Object waves reconstructed from such focal series were processed to study oxygen vacancies as well as octahedral tilts and distortions induced by the slightly different lattice parameters of PCMO and STO.