论文标题
高能量的局部轨道和电子 - 光子相互作用对六角硼硼化硼的带隙和光谱的影响
The influence of high-energy local orbitals and electron-phonon interactions on the band gaps and optical spectra of hexagonal boron nitride
论文作者
论文摘要
We report $ab$ $initio$ band diagram and optical absorption spectra of hexagonal boron nitride ($h$-BN), focusing on unravelling how the completeness of basis set for $GW$ calculations and how electron-phonon interactions (EPIs) impact on them.基集的完整性是在以前的光谱计算中很少讨论$ h $ bn的问题，这对于提供融合的准粒子带隙至关重要。在三个不同代码之间的比较中，我们证明，通过在全电子线性的增强平面波中包括高能量的本地轨道，基于$ GW $计算，Quasiparticle Direct和基本间接频段间隙通过$ $ \ $ \ sim $ 0.2 ev扩大，分别为6.81 ev和6.81 ev和6.25 ev和6.25 ev $ $ $ gw__ $ gw__级别。另一方面，EPIS在0 K时分别将它们降低到6.62 eV和6.03 eV，在300 K处分别将它们降低到6.60 eV和5.98 eV。具有夹紧晶体结构，吸收光谱的第一个峰值为6.07 eV，源自$ K $ $ k $ $ k $ $ k $ $ k $ $ k $ $ k $ $ k $ $ k $。在将EPIPNARFARIGATIAL的准粒子包括在伯特 - 盐方程中之后，激子耦合将第一个峰转移到300 K时的第5.83 eV，低于$ \ sim $ 6.00 ev的实验值。对于$ ab $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $的说明，没有合适参数的描述。
We report $ab$ $initio$ band diagram and optical absorption spectra of hexagonal boron nitride ($h$-BN), focusing on unravelling how the completeness of basis set for $GW$ calculations and how electron-phonon interactions (EPIs) impact on them. The completeness of basis set, an issue which was seldom discussed in previous optical spectra calculations of $h$-BN, is found crucial in providing converged quasiparticle band gaps. In the comparison among three different codes, we demonstrate that by including high-energy local orbitals in the all-electron linearized augmented plane waves based $GW$ calculations, the quasiparticle direct and fundamental indirect band gaps are widened by $\sim$0.2 eV, giving values of 6.81 eV and 6.25 eV respectively at the $GW_0$ level. EPIs, on the other hand, reduce them to 6.62 eV and 6.03 eV respectively at 0 K, and 6.60 eV and 5.98 eV respectively at 300 K. With clamped crystal structure, the first peak of the absorption spectrum is at 6.07 eV, originating from the direct exciton contributed by electron transitions around $K$ in the Brillouin zone. After including the EPIs-renormalized quasiparticles in the Bethe-Salpeter equation, the exciton-phonon coupling shifts the first peak to 5.83 eV at 300 K, lower than the experimental value of $\sim$6.00 eV. This accuracy is acceptable to an $ab$ $initio$ description of excited states with no fitting parameter.
