Department of Chemistry, Princeton University, Princeton, NJ 08544-5263, USA.
Phys Chem Chem Phys. 2011 Sep 7;13(33):15189-99. doi: 10.1039/c1cp20829b. Epub 2011 Jul 14.
Quantitative characterization of low-lying excited electronic states in materials is critical for the development of solar energy conversion materials. The many-body Green's function method known as the GW approximation (GWA) directly probes states corresponding to photoemission and inverse photoemission experiments, thereby determining the associated band structure. Several versions of the GW approximation with different levels of self-consistency exist in the field. While the GWA based on density functional theory (DFT) works well for conventional semiconductors, less is known about its reliability for strongly correlated semiconducting materials. Here we present a systematic study of the GWA using hematite (α-Fe(2)O(3)) as the benchmark material. We analyze its performance in terms of the calculated photoemission/inverse photoemission band gaps, densities of states, and dielectric functions. Overall, a non-self-consistent G(0)W(0) using input from DFT+U theory produces physical observables in best agreement with experiments.
定量描述材料中低能激发电子态对于开发太阳能转换材料至关重要。多体格林函数方法，即 GW 近似（GWA），可以直接探测与光电子和逆光电子实验相对应的态，从而确定相关的能带结构。该领域存在不同自洽程度的几种 GW 近似版本。基于密度泛函理论（DFT）的 GWA 在常规半导体中表现良好，但对于强关联半导体材料的可靠性了解较少。在这里，我们以赤铁矿（α-Fe(2)O(3)）作为基准材料，对 GWA 进行了系统研究。我们根据计算出的光电子/逆光电子带隙、态密度和介电函数来分析其性能。总的来说，使用 DFT+U 理论输入的非自洽 G(0)W(0) 产生的实验物理观测结果与实验结果最吻合。
