Methods of crystal growth of rare earth garnets without precious metal crucibles are extensively developed nowadays. This work addresses defects forming in carbon‐containing Lu3Al5O12 crystals grown in Ar + CO atmosphere in W crucibles. The influence of carbon admixture on formation energies and oxidation states of intrinsic defects has been studied by ab initio calculations and optical spectroscopy. 21 types of isolated and complex defects have been considered in oxygen‐poor conditions of crystal growth in Ar + CO reducing atmosphere and oxygen‐rich conditions of postgrowth annealing of crystals in air. Despite the same type of crystalline structure and similar chemical compositions of Y3Al5O12 and Lu3Al5O12, the remarkable differences in formation mechanisms of color centers have been found in these materials. The conducted modeling suggests a reduced likelihood of the formation of positively charged carbon‐related defects responsible for color center formation, such as carbon occupying the oxygen site (CO) and interstitial carbon (Ci), in LuAG:C when compared to YAG:C. Regarding optical properties, fewer types of color centers are observed in LuAG:C absorption spectra, indicating a good agreement between simulation and experimental data. This study provides fresh insights into the mechanisms behind color center formation in rare earth garnets.

中文翻译：

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碳掺杂对Y3Al5O12和Lu3Al5O12本征缺陷稳定性的影响

目前，无需贵金属坩埚的稀土石榴石晶体生长方法已得到广泛发展。这项工作解决了含碳 Lu 中形成的缺陷3铝5氧12在Ar+CO气氛中在W坩埚中生长晶体。通过从头计算和光谱研究了碳混合物对本征缺陷的形成能和氧化态的影响。在 Ar + CO 还原气氛中晶体生长的贫氧条件和空气中晶体生长后退火的富氧条件下，考虑了 21 种孤立且复杂的缺陷。尽管 Y 具有相同类型的晶体结构和相似的化学成分3铝5氧12和卢3铝5氧12，在这些材料中发现了色心形成机制的显着差异。进行的建模表明，与色心形成相关的带正电碳相关缺陷的形成可能性降低，例如碳占据氧位点（C氧）和间隙碳（C我），在 LuAG:C 中与 YAG:C 相比。关于光学特性，在 LuAG:C 吸收光谱中观察到的色心类型较少，表明模拟数据与实验数据之间具有良好的一致性。这项研究为稀土石榴石色心形成背后的机制提供了新的见解。