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O: Fachverband Oberflächenphysik

O 79: Oxide Surfaces III

O 79.9: Vortrag

Donnerstag, 14. März 2013, 18:00–18:15, H45

Is the BaTiO₃ (001)-(2x1) reconstruction magnetic ? — •Holger. L. Meyerheim¹, A. Ernst¹, K. Mohseni¹, I.V. Maznichenko², S. Ostanin¹, F. Klimenta¹, N. Jedrecy³, W. Feng¹, I. Mertig², R. Felici⁴, and J. Kirschner¹ — ¹Max-Planck-Institut f. Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany — ²Institut f. Physik, Martin-Luther-Univ. Halle-Wittenberg, D-06099 Halle, Germany — ³Institut des Nano Sciences de Paris, UPMC-Sorbonne Univ., CNRS-UMR7588, 75005 Paris, France — ⁴ESRF, B. P. 220, F-38043 Grenoble Cedex, France

Though BaTiO₃ is the prototype perovskite type ferroelectric and its (2x1) reconstruction has been observed more than 30 years ago [1] no detailed analysis of its atomic geometry has been reported so far. We have carried out a surface x-ray diffraction analysis of the BTO(001)-(2×1) reconstructed surface [2]. While the crystal is terminated by two TiO₂ layers similarly to SrTiO₃(001)-(2×1) [3], we find that one Ti-atom of the top TiO₂ layer resides in a tetragonal pyramidal oxygen environment. Ab initio calculations based on this structure model suggest that the surface is metallic and magnetic involving local magnetic moments up to 2µ_B in magnitude located at surface Ti and O atoms.

References: [1] R. Courths, Phys. Status Solidi B 100, 135 (1980) [2] H. L. Meyerheim, A. Ernst, K. Mohseni, I. V. Maznichenko, S. Ostanin, F. Klimenta, N. Jedrecy, W. Feng, I. Mertig, R. Felici,, and J. Kirchner, Phys. Rev. Lett. 108, 215502 (2012) [3] N. Erdman, K.R. Poeppelmeier, M. Asta et al., Nature 419, 55 (2002)