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Procedure for LEED I − V structural analysis of metal oxide surfaces: Ca 1.5 Sr 0.5 RuO 4 <mml:mo…

2007; American Physical Society; Volume: 75; Issue: 3 Linguagem: Inglês

10.1103/physrevb.75.035408

1550-235X

V. B. Nascimento, R. G. Moore, J. Rundgren, Jiandi Zhang, Lei Cai, Rongying Jin, David Mandrus, E. W. Plummer,

X-ray Diffraction in Crystallography

Transition metal oxides (TMOs) are famous for the intimate coupling between the lattice, electrons, and spin, creating exotic functionality. Creating a surface, breaking the symmetry, should result in lattice distortions that due to the close coupling could create different ``surface phases.'' Historically it has been very difficult to use low energy electron diffraction $I\ensuremath{-}V$ to quantitatively determine the surface structure of TMOs. A signature of this problem is the large values commonly reported in the literature of the Pendry reliability factor $({R}_{\mathrm{P}})$, which is used to quantify the agreement between experimental data and calculated diffraction. In this paper we describe a consistent procedure for determining the phase shifts using an optimized muffin-tin potential approach combined with an energy-dependent real and imaginary inner potential. This procedure is used to determine the surface structure of the layered TMO ${\mathrm{Ca}}_{1.5}{\mathrm{Sr}}_{0.5}{\mathrm{RuO}}_{4}$. An acceptable Pendry reliability factor is achieved $({R}_{\mathrm{P}}=0.28)$.