Sulfur Atoms Adsorbed on Cu(100) at Low Coverage: Characterization and Stability against Complexation.
Sulfur Atoms Adsorbed on Cu(100) at Low Coverage: Characterization and Stability against Complexation.
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DOI：
10.1021/acs.jpcb.7b07046
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发表时间：
2017-09
期刊：
影响因子：
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通讯作者：
Holly Walen;Da‐Jiang Liu;Junepyo Oh;Hyun Jin Yang;P. Spurgeon;Yousoo Kim;P. Thiel
中科院分区：
文献类型：
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作者：
Holly Walen;Da‐Jiang Liu;Junepyo Oh;Hyun Jin Yang;P. Spurgeon;Yousoo Kim;P. Thiel
使用扫描隧道显微镜，我们表征的尺寸和偏置依赖的形状的硫原子在Cu（100）在低覆盖率（低于0.1单层）和低温（淬火从300至5 K）。在低覆盖率下，硫原子比台阶更重地填充Cu（100）阶地，但随着覆盖率接近0.1单层，紧密堆积的台阶边缘变得完全填充，硫原子占据台阶顶部的位置。密度泛函理论（DFT）证实了优先人口的梯田在低覆盖率以及步骤吸附网站。在实验中，当硫覆盖率接近0.1单层时，在梯田上出现了类似p（2 × 2）原子排列的小区域。使用DFT，晶格气模型已经开发，并根据该模型的Monte Carlo模拟与观察到的梯田配置进行了比较。一个模型包含八对相互作用能，所有排斥，给出定性协议。实验表明，在覆盖率为0.09的Cu（100）表面上，原子吸附硫是唯一的吸附态。没有Cu-S络合物。相比之下，先前的工作表明，在可比条件下，Cu（111）上形成Cu 2S 3络合物。基于DFT，这种差异可以主要归因于Cu（100）比Cu（111）更强的硫吸附。
Using scanning tunneling microscopy, we characterize the size and bias-dependent shape of sulfur atoms on Cu(100) at low coverage (below 0.1 monolayers) and low temperature (quenched from 300 to 5 K). Sulfur atoms populate the Cu(100) terraces more heavily than steps at low coverage, but as coverage approaches 0.1 monolayers, close-packed step edges become fully populated, with sulfur atoms occupying sites on top of the step. Density functional theory (DFT) corroborates the preferential population of terraces at low coverage as well as the step adsorption site. In experiment, small regions with p(2 × 2)-like atomic arrangements emerge on the terraces as sulfur coverage approaches 0.1 monolayer. Using DFT, a lattice gas model has been developed, and Monte Carlo simulations based on this model have been compared with the observed terrace configurations. A model containing eight pairwise interaction energies, all repulsive, gives qualitative agreement. Experiment shows that atomic adsorbed sulfur is the only species on Cu(100) up to a coverage of 0.09 monolayers. There are no Cu-S complexes. In contrast, prior work has shown that a Cu2S3 complex forms on Cu(111) under comparable conditions. On the basis of DFT, this difference can be attributed mainly to stronger adsorption of sulfur on Cu(100) as compared with Cu(111).