物理学院 School of Physics, Nanjing University

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Surface Structure and Reactivity of Selected Perovskite Oxides

2016年01月04日

报告人:  Prof. Ulrike Diebold 
                  Institute of Applied Physics, Vienna University of Technology (TU Wien), 
时 间:       2016年1月5日(周二)上午10:00 
地 点:       唐仲英楼B501 
 
摘要:
    Ternary oxides with the perovskite structure exhibit an intriguingly
rich variety in their physical and chemical properties. The surfaces of these promising
materials are equally complex and generally poorly understood. Here we report an overview
of surface studies of two perovskite oxides, the prototypical SrTiO3 in (110) orientation
and Sr3RuO7, the n=2 member of the Ruddlesden-Popper series.
    The surface of the layered compound, Sr3RuO7, is structurally quite
simple: cleaving in UHV yields a SrO-terminated layer, which is essentially defect-free,
except for impurities in the bulk material [1]. The surface is very reactive towards
components of the residual gas, however. CO, CO2, and H2O adsorb readily and form
adsorption complexes [2, 3]. SrTiO3(110) is polar and exhibits a series of reconstructions
that can be controlled by adjusting the chemical potential of its constituents, i.e. by
evaporating appropriate amounts of Sr and Ti and annealing in O2. The (nx1)
reconstructions consist of a monolayer of titania with tetrathedrally-coordinated Ti atoms
that are arranged in corner-sharing rings [4]. When the Ti chemical potential is increased,
the surface switches over to a (2xm) symmetry with a titania layer that is composed of Ti
in octahedral coordination. These stoichiometry-dependent, facile structural changes have
a profound effect on surface reactivity, and on the homoepitaxial growth of SrTiO3 during
pulsed laser deposition.
    [1]B. Stöger, et al, Phys. Rev. B 90 (2014) 165438.
    [2]B. Stöger, et al., Phys Rev Lett 113 (2014) 116101.
    [3]D. Halwidl et al. Nature Mater. (2015).
    [4]Z. Wang et al., Phys. Rev. Lett. Phys Rev Lett 111 (2013) 056101.
 
个人简介:
    Ulrike Diebold is a full professor at the Institute of Applied Physics,
Vienna University of Technology (TU Wien). Diebold conducts research in experimental
surface science with an emphasis on metal oxide surfaces. She has published close to 200
peer-reviewed articles, and has given over 250 invited talks including several named
lectures. Her articles have been cited more than 13,000 times, and currently the ISI lists
her with an h-index of 53. Diebold serves on several editorial and other advisory boards
and is currently a divisional associate editor of Physical Review Letters. She has been
elected Fellow of AVS, APS, and AAAS, and is a member of the Austrian, the German, and
the European Academy of Sciences. She is a recipient of several international awards,
most recently an Advanced Research Grant from the European Research Council, the Adamson
Award of the American Chemical Society, the Blaise Pascal Medal in Materials Science,
and the Wittgenstein Prize, the highest science award in Austria.

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