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arXiv 0709.4162cond-mat.mes-hall
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纳米尺度电导的基准密度泛函理论计算

Benchmark density functional theory calculations for nano-scale conductance

M. Strange, I. S. Kristensen, K. S. Thygesen

摘要:

我们提出了一套基准计算的Kohn-Sham弹性传输函数的五个代表性的单分子结。透射函数的计算使用两种不同的密度泛函理论(DFT)的方法,即超软赝势平面波代码结合最大本地化的Wannier函数,和范数守恒赝势代码Siesta适用于原子轨道基组。对于所有的系统,我们发现的Siesta传输函数收敛到平面波的结果作为Siesta基扩大。总的来说,我们发现,双ζ和偏振的原子基础是足够的(在某些情况下,甚至是必要的),以确保与平面波计算的定量协议。我们观察到一个系统的下移位的午睡传输函数相对于平面波的结果。随着原子轨道基的增大,这种效应减弱,然而,收敛可能相当慢。

英文摘要:

We present a set of benchmark calculations for the Kohn-Sham elastic transmission function of five representative single-molecule junctions. The transmission functions are calculated using two different density functional theory (DFT) methods, namely an ultrasoft pseudopotential plane wave code in combination with maximally localized Wannier functions, and the norm-conserving pseudopotential code Siesta which applies an atomic orbital basis set. For all systems we find that the Siesta transmission functions converge toward the plane-wave result as the Siesta basis is enlarged. Overall, we find that an atomic basis with double-zeta and polarization is sufficient (and in some cases even necessary) to ensure quantitative agreement with the plane-wave calculation. We observe a systematic down shift of the Siesta transmission functions relative to the plane-wave results. The effect diminishes as the atomic orbital basis is enlarged, however, the convergence can be rather slow.

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