Department of Physics, Faculty of Science, University of Ostrava, 30. dubna 22, 701 03 Ostrava, Czech Republic.
Phys Chem Chem Phys. 2019 Feb 13;21(7):3999-4005. doi: 10.1039/c8cp07328g.
Many-body perturbational GW approximation in conjunction with the Bethe-Salpeter equation (BSE) has been employed to calculate accurate electronic and optical band gaps of bulk hexagonal boron nitride (h-BN) in the two most important stacking configurations, AA' and AB. The carefully converged results revealed h-BN as an indirect material (indirect gap ≈ 6.1 eV) with a huge excitonic effect (≈0.8 eV) in perfect agreement with recent experiments [Nat. Photonics, 2016, 10, 262; Appl. Phys. Lett., 2016, 109, 122101]. The K-H region of the first Brillouin zone has been shown as the most important for lowest optical excitations in h-BN. Surprisingly, simple scissor corrected DFT has described h-BN band structure at the GW level and subsequent time-dependent DFT with a suitable exchange correlation kernel has provided absorption spectra similar to the full GW+BSE spectra.
采用多体微扰 GW 近似结合玻恩-奥本海默方程 (BSE)，我们计算了在两种最重要的堆叠构型 AA' 和 AB 中体相六方氮化硼 (h-BN) 的精确电子和光学带隙。经过仔细收敛的结果表明 h-BN 是一种间接材料（间接带隙 ≈ 6.1 eV），具有巨大的激子效应（≈0.8 eV），与最近的实验结果完全一致[Nat. Photonics, 2016, 10, 262; Appl. Phys. Lett., 2016, 109, 122101]。第一布里渊区的 K-H 区被证明是 h-BN 中最低光学激发最重要的区域。令人惊讶的是，简单的修正裁剪密度泛函理论 (DFT) 在 GW 水平上描述了 h-BN 的能带结构，随后使用合适的交换相关核的时间相关 DFT 提供了与全 GW+BSE 光谱相似的吸收光谱。
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