$\mathrm{M}{\mathrm{g}}_3{\mathrm{N}}_2$ is a promising material for light-emitting-diode applications. However, the microscopic origin of the broad yellow photoluminescence in $\mathrm{M}{\mathrm{g}}_3{\mathrm{N}}_2$ remains unknown. Here, defect properties and defect-related optical transitions are investigated based on the hybrid functional calculation. Our results show that the nitrogen vacancy introduces multiple localized defect states within the band gap, which play a dominant role in luminescent properties of $\mathrm{M}{\mathrm{g}}_3{\mathrm{N}}_2$. Common impurities like hydrogen, oxygen, and carbon and their complexes with native defects are also studied. Compared with isolated ${\mathrm{V}}_{\mathrm{Mg}}, {\mathrm{V}}_{\mathrm{Mg}}$-H and ${\mathrm{V}}_{\mathrm{Mg}}-{\mathrm{O}}_{\mathrm{N}}$ complexes have shallower transition levels. Our calculated optical excitation and emission peaks associated with isolated ${\mathrm{V}}_{\mathrm{N}}$ are in good agreement with those observed in experiments. In addition, the impurity ${\mathrm{C}}_{\mathrm{N}}$ is also a potential source for the observed yellow emission in $\mathrm{M}{\mathrm{g}}_3{\mathrm{N}}_2$.

中文翻译：

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Mg3N2中缺陷及其与缺陷相关的发光的密度泛函研究

$\mathrm{中号}{\mathrm{G}}_3{\mathrm{ñ}}_2$是用于发光二极管应用的有前途的材料。然而，宽泛的黄色光致发光的微观起源$\mathrm{中号}{\mathrm{G}}_3{\mathrm{ñ}}_2$仍然未知。在此，基于混合函数计算研究了缺陷性质和与缺陷有关的光学跃迁。我们的结果表明，氮空位在带隙内引入了多个局部缺陷状态，这些状态在LED的发光特性中起着主导作用。$\mathrm{中号}{\mathrm{G}}_3{\mathrm{ñ}}_2$。还研究了氢，氧和碳等常见杂质及其与天然缺陷的配合物。与孤立相比${\mathrm{V}}_{镁}， {\mathrm{V}}_{镁}$-H和 ${\mathrm{V}}_{镁}-{\mathrm{Ø}}_{\mathrm{ñ}}$复合体的过渡水平较浅。我们计算出的与分离的光相关的光激发和发射峰${\mathrm{V}}_{\mathrm{ñ}}$与实验中观察到的非常吻合。另外，杂质${\mathrm{C}}_{\mathrm{ñ}}$ 也是观察到的黄光发射的潜在来源 $\mathrm{中号}{\mathrm{G}}_3{\mathrm{ñ}}_2$。