Electronic level alignment at a metal-molecule interface from a short-range hybrid functional
Electronic level alignment at a metal-molecule interface from a short-range hybrid functional
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DOI：
10.1063/1.3655357
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发表时间：
2011-10-28
影响因子：
4.4
通讯作者：
Kronik, Leeor
中科院分区：
文献类型：
--
作者：
Biller, Ariel;Tamblyn, Isaac;Kronik, Leeor
杂化泛函在描述有机材料的电子结构时，往往比半局域泛函有明显的改进。由于短程杂化泛函，特别是Heyd-Scus eria-Ernzerhof(HSE)泛函也可以很好地描述金属的电子结构，因此考察它们在多大程度上能够正确地描述金属-有机界面的电子结构是很有意义的。在这里，我们通过比较两个典型体系的HSE计算和GW近似下的多体微扰理论计算，或与实验光电子能谱数据来解决这个问题：苯在石墨上，苯二胺在金上。对于这两种情况，我们发现，尽管HSE产生的结果比半局部泛函的结果更接近实验，但HSE的预测在数量上仍然缺乏类似于1 eV的结果。我们指出，这种定量失效的产生是因为HSE没有正确地捕捉到有机的基本能隙或金属的重整化。这些差异可以追溯到缺少长程交换和关联分量，这一解释适用于任何常规或短程混合泛函。(C)2011年美国物理研究所。[DOI：10.1063/1.3655357]
Hybrid functionals often exhibit a marked improvement over semi-local functionals in the description of the electronic structure of organic materials. Because short-range hybrid functionals, notably the Heyd-Scuseria-Ernzerhof (HSE) functional, can also describe the electronic structure of metals reasonably well, it is interesting to examine to which extent they can correctly describe the electronic structure at metal-organic interfaces. Here, we address this question by comparing HSE calculations with many-body perturbation theory calculations in the GW approximation, or with experimental photoemission data, for two prototypical systems: benzene on graphite and benzene diamine on gold. For both cases, we find that while HSE yields results that are somewhat closer to experiment than those of semi-local functionals, the HSE prediction is still lacking quantitatively by similar to 1 eV. We show that this quantitative failure arises because HSE does not correctly capture the fundamental gap of the organic or its renormalization by the metal. These discrepancies are traced back to missing long-range exchange and correlation components, an explanation which applies to any conventional or short-range hybrid functional. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3655357]