Dielectric embedding GW for weakly coupled molecule-metal interfaces.
Dielectric embedding GW for weakly coupled molecule-metal interfaces.
复制标题
用于弱耦合分子-金属界面的介电嵌入GW。
DOI：
10.1063/1.5140972
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Zhen
中科院分区：
文献类型：
--
作者：
Zhen
分子-金属界面在纳米材料科学中有着广泛的应用。从第一性原理准确表征其电子结构是理解材料和器件性能的关键。多体微扰理论中的GW方法是最先进的，并且原则上可以产生与实验定量一致的精确准粒子能级和界面能级排列。然而，接口是大型异构系统，目前具有挑战性的第一原理GW计算。在这项工作中，我们开发了一种基于GW的分子-金属界面的电介质嵌入方法，在不牺牲精度的情况下显著降低了直接GW的计算成本。具体而言，我们只在分子吸附物的模拟单元中进行明确的GW计算，其中嵌入了金属基底的介电效应。这是可能的，通过一个真实的空间截断的基板极化率和使用的界面等离子体频率在吸附物GW计算。在这里，我们专注于弱耦合分子-金属界面处的能级对准，即，分子前线轨道共振和基底费米能级之间的能量差。我们展示了我们的方法，并评估了一些GW为基础的近似使用两个研究良好的系统，苯吸附在Al（111）和石墨（0001）表面上。
Molecule-metal interfaces have a broad range of applications in nanoscale materials science. Accurate characterization of their electronic structures from first-principles is key in understanding material and device properties. The GW approach within many-body perturbation theory is the state-of-the-art and can in principle yield accurate quasiparticle energy levels and interfacial level alignments that are in quantitative agreement with experiments. However, the interfaces are large heterogeneous systems that are currently challenging for first-principles GW calculations. In this work, we develop a GW-based dielectric embedding approach for molecule-metal interfaces, significantly reducing the computational cost of direct GW without sacrificing the accuracy. To be specific, we perform explicit GW calculations only in the simulation cell of the molecular adsorbate, in which the dielectric effect of the metallic substrate is embedded. This is made possible via a real-space truncation of the substrate polarizability and the use of the interface plasma frequency in the adsorbate GW calculation. Here, we focus on the level alignment at weakly coupled molecule-metal interfaces, i.e., the energy difference between a molecular frontier orbital resonance and the substrate Fermi level. We demonstrate our method and assess a few GW-based approximations using two well-studied systems, benzene adsorbed on the Al (111) and on the graphite (0001) surfaces.