arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 0907.4320cond-mat.mtrl-scicond-mat.other
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2 H-、4 H-和6 H- SiC(000 - 1)和SiC(000-1)清洁表面电子性质的比较DFT研究:表面Stark效应的意义

A comparative DFT study of electronic properties of 2H-, 4H- and 6H-SiC(0001) and SiC(000-1) clean surfaces: Significance of the surface Stark effect

Jakub Soltys, Jacek Piechota, Michal Lopuszynski, Stanislaw Krukowski

摘要:

采用DFT方法对不同厚度的SiC表面板进行了模拟,分析了由于费米能级钉扎在SiC表面板两侧产生的均匀电场。结果表明,对于较厚的平板,电场是不均匀的,这一事实与表面态电荷有关。利用电子密度和电势分布,证明了为了进行高精度的模拟,有必要考虑足够数量的Si-C层。我们表明,使用12个双原子层导致令人满意的结果。它还表明,相对侧板终止的变化,无论是由不同类型的原子或由它们的位置,可以用来调整板内的电场,创建一个工具,用于模拟表面性质,这取决于在半导体的大部分掺杂。使用这些模拟结果发现,取决于电场,表面态的能量以不同于体态能量的方式变化。这个判据可以用来区分Shockley和Tamm表面态。利用场相关密度泛函方法对2 H-、4 H-、6 H-SiC(0001)和SiC($000 \bar{1}$)三种洁净表面的电子性质,即表面态的能量和类型进行了分析和比较。

英文摘要:

Electric field, uniform within the slab, emerging due to Fermi level pinning at its both sides is analyzed using DFT simulations of the SiC surface slabs of different thickness. It is shown that for thicker slab the field is nonuniform and this fact is related to the surface state charge. Using the electron density and potential profiles it is proved that for high precision simulations it is necessary to take into account enough number of the Si-C layers. We show that using 12 diatomic layers leads to satisfactory results. It is also demonstrated that the change of the opposite side slab termination, both by different type of atoms or by their location, can be used to adjust electric field within the slab, creating a tool for simulation of surface properties, depending on the doping in the bulk of semiconductor. Using these simulations it was found that, depending on the electric field, the energy of the surface states changes in a different way than energy of the bulk states. This criterion can be used to distinguish Shockley and Tamm surface states. The electronic properties, i.e. energy and type of surface states of the three clean surfaces: 2H-, 4H-, 6H-SiC(0001), and SiC($000 \bar{1}$) are analyzed and compared using field dependent DFT simulations.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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