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arXiv 1305.6512cond-mat.mtrl-sci
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固体、分子和二维材料的准粒子GW计算

Quasiparticle GW calculations for solids, molecules and 2D materials

Falco Hüser, Thomas Olsen, Kristian S. Thygesen

摘要:

我们提出了一个平面波实现的G 0 W 0近似内的投影增广波方法代码GPAW。十块体半导体和绝缘体的计算带隙平均偏离实验值0.2 eV(~ 5%)-唯一的例外是ZnO,其计算带隙过低约1 eV。类似的相对偏差被发现为32个小分子的测试集的电离势。衬底筛选的准粒子的能量和费米速度在支持的二维材料的正确描述的重要性是由石墨烯/h-BN接口的情况下说明。由于周期性重复的图像之间的长程库仑相互作用,使用截断的相互作用被发现是必不可少的,以获得收敛的结果为2D材料。对于所有的系统研究,等离子体激元极点近似被发现再现全频率的结果在0.2 eV内的计算速度有显着的增益。作为G 0 W 0的替代方案,有效的本地GLLBSC潜力产生比PBE 0杂交显著更好的结果。为了完整,我们提供了一个数学上严格和物理上透明的介绍准粒子态的概念。

英文摘要:

We present a plane wave implementation of the G0W0 approximation within the projector augmented wave method code GPAW. The computed band gaps of ten bulk semiconductors and insulators deviate on average by 0.2 eV (~ 5 %) from the experimental values - the only exception being ZnO where the calculated band gap is around 1 eV too low. Similar relative deviations are found for the ionization potentials of a test set of 32 small molecules. The importance of substrate screening for a correct description of quasiparticle energies and Fermi velocities in supported 2D materials is illustrated by the case of graphene/h-BN interfaces. Due to the long range Coulomb interaction between periodically repeated images, the use of a truncated interaction is found to be essential for obtaining converged results for 2D materials. For all systems studied, a plasmon pole approximation is found to reproduce the full frequency results to within 0.2 eV with a significant gain in computational speed. As alternative to G0W0, the efficient local GLLBSC potential yields significantly better results than the PBE0 hybrid. For completeness, we provide a mathematically rigorous and physically transparent introduction to the notion of quasiparticle states.

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