Structural and electronic characterization of the MgO/Mo(001) interface using STM

SURFACE SCIENCE

卷:604

Article

Benia, H. M.¹  Myrach, P.¹  Nilius, N.¹  Freund, H. -J.¹ 

[1] Max Planck Gesell, Fritz Haber Inst, D-14195 Berlin, Germany

关键词: Oxide thin films;    Nucleation and growth;    Coincidence lattice;    MgO;    Mo;    Scanning tunneling microscopy and spectroscopy;   

DOI  :  10.1016/j.susc.2009.12.011

来源: Elsevier

【 摘 要 】

The nucleation and growth of ultrathin MgO films on Mo(0 0 1) have been investigated with scanning tunneling microscopy and spectroscopy. In the initial growth stage, the MgO forms rather uniform islands with rectangular shapes and defined orientation. This behavior reflects a preferential binding of the oxide O ions to the top positions in the Mo support, which can be realized only in confined areas due to the MgO/Mo lattice mismatch. At monolayer coverage, a characteristic square pattern becomes visible in the STM, indicating the formation of an MgO/Mo coincidence lattice. In the coincidence cell, the interface registry alternates between O and Mg ions being in Mo top positions. The resulting imaging contrast in the STM is dominated by a work-function modulation and not by a topographic effect, as demonstrated with STM-conductance and light-emission spectroscopy. The modulated work function in the coincidence cell is assigned to a small buckling of the oxide film with either O or Mg ions being closer to the Mo surface. (C) 2009 Elsevier B.V. All rights reserved.

【 授权许可】

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