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arXiv 0808.0105cond-mat.mtrl-sci
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重叠Muffin-Tin近似

The Overlapping Muffin-Tin Approximation

M. Zwierzycki, O. K. Andersen

摘要:

我们提出的形式主义,并证明了使用重叠的松饼罐近似(OMTA)。这将一个完整的势拟合到球对称短程势阱加上一个常数的叠加。对于这种形式的单电子势,标准的多重散射方法可以正确地求解薛定谔方程到势重叠的一阶。选择一个增广的平面波方法作为源的全部潜力,我们说明了钻石结构的硅的过程。首先,我们比较了Si中心OMTA中的势与全势,然后比较了相应的OMTA $N$阶Muffin-tin轨道和全势LAPW能带结构.我们发现,后者同意定性为一个广泛的重叠和价带有一个均方根偏差为20毫电子伏/电子为30%的径向重叠。重叠越小,势越差,重叠越大,多次散射法的二阶误差越大。为了进一步消除小重叠的频带的平均误差是简单的。

英文摘要:

We present the formalism and demonstrate the use of the overlapping muffin-tin approximation (OMTA). This fits a full potential to a superposition of spherically symmetric short-ranged potential wells plus a constant. For one-electron potentials of this form, the standard multiple-scattering methods can solve Schrödingers' equation correctly to 1st order in the potential overlap. Choosing an augmented-plane-wave method as the source of the full potential, we illustrate the procedure for diamond-structured Si. First, we compare the potential in the Si-centered OMTA with the full potential, and then compare the corresponding OMTA $N$-th order muffin-tin orbital and full-potential LAPW band structures. We find that the two latter agree qualitatively for a wide range of overlaps and that the valence bands have an rms deviation of 20 meV/electron for 30% radial overlap. Smaller overlaps give worse potentials and larger overlaps give larger 2nd-order errors of the multiple-scattering method. To further remove the mean error of the bands for small overlaps is simple.

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