Tip-Dependent Scanning Tunneling Microscopy Imaging of Ultrathin FeO Films on Pt(111)

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• 作者：Lindsay R. Merte ; Lars C. Grabow ; Guowen Peng ; Jan Knudsen ; Helene Zeuthen ; Wilhelmine Kudernatsch ; Soeren Porsgaard ; Erik L忙gsgaard ; Manos Mavrikakis ; Flemming Besenbacher
• 刊名：Journal of Physical Chemistry C
• 出版年：2011
• 出版时间：February 10, 2011
• 年：2011
• 卷：115
• 期：5
• 页码：2089-2099
• 全文大小：1392K
• 年卷期：v.115,no.5(February 10, 2011)
• ISSN：1932-7455

文摘

High-resolution scanning tunneling microscope (STM) images of moir茅-structured FeO films on Pt(111) were obtained in a number of different tip-dependent imaging modes. For the first time, the STM images are distinguished and interpreted unambiguously with the help of distinct oxygen-vacancy dislocation loops in the FeO moir茅 structure. The experimental STM results are compared with the results of electronic structure calculations within the DFT+U scheme for a realistic (鈭?1 脳 鈭?1)R5.2掳 moir茅 FeO unit cell supported on Pt(111) as well as with the results from previous studies. We find that one type of STM imaging mode, showing both Fe and O atoms, agrees well with simulated STM images, indicating that the simple Tersoff鈭扝amann theory is partially valid for this imaging mode. In addition, we identify other distinct, element-specific imaging modes which reveal a strong dependence on the specific tip apex state and likely result from specific tip鈭抯ample chemical interactions. From the present STM results we show that several of the previously published conclusions for the FeO system have to be revisited.