Steps on Fe3O4(100): STM measurements and theoretical calculations
Steps on Fe3O4(100): STM measurements and theoretical calculations
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DOI：
10.1103/physrevb.73.235418
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发表时间：
2006-06
影响因子：
3.7
通讯作者：
Hui‐Qiong Wang;E. Altman;V. Henrich
中科院分区：
文献类型：
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作者：
Hui‐Qiong Wang;E. Altman;V. Henrich
用扫描隧道显微镜(STM)对天然单晶样品的台阶结构进行了测量。阶跃边缘沿$[110]$和$[1\overline{1}0]$方向出现。对于$4.2\ifmmode\pm\else\textpm\fi{}0.3\phantom{\rule{0.3em}{0ex}}\mathrm{\AA{}}$，的台阶高度，台阶边缘是直的，而对于$2.1\ifmmode\pm\else\textpm\fi{}0.2\phantom{\rule{0.3em}{0ex}}\mathrm{\AA{}}$，的台阶高度，交替的台阶边缘是直的和锯齿状的。直的(锯齿状)台阶边缘与上露台上的八面体铁排平行(垂直)。配位不饱和度和超额表面电荷的概念被用来预测沿台阶边缘哪些原子构型可能最稳定。我们的计算表明，与上阶地上的八面体铁排平行的台阶预计比垂直于它们的台阶更稳定，这与我们的STM观测结果一致。这种台阶稳定性与梯田结构和台阶高度无关。
Scanning tunneling microscopy (STM) measurements of the step structure on natural single-crystal samples of ${\mathrm{Fe}}_{3}{\mathrm{O}}_{4}(100)$ have been performed. Step edges are found to occur along both $[110]$ and $[1\overline{1}0]$ directions. For step heights of $4.2\ifmmode\pm\else\textpm\fi{}0.3\phantom{\rule{0.3em}{0ex}}\mathrm{\AA{}}$, the step edges are found to be straight, whereas for step heights of $2.1\ifmmode\pm\else\textpm\fi{}0.2\phantom{\rule{0.3em}{0ex}}\mathrm{\AA{}}$, alternate step edges are straight and jagged. The straight (jagged) step edges are parallel (perpendicular) to the octahedral iron rows on the upper terrace. The concepts of coordinative unsaturation and excess surface charge are used to predict which atomic geometries are likely to be most stable along step edges. Our calculations show that steps parallel to the octahedral iron rows on the upper terrace are expected to be more stable than those perpendicular to them, in agreement with our STM observations. This step stability is found to be independent of both terrace structure and step height.