Kolobov Alexander V, Kuznetsov Vladimir G, Krbal Milos, Zabotnov Stanislav V
Institute of Physics, Herzen State Pedagogical University of Russia, 48 Moïka Emb., St. Petersburg 191186, Russia.
Ioffe Institute, 26 Polytechnicheskaya Street, St. Petersburg 191186, Russia.
Materials (Basel). 2023 Oct 9;16(19):6602. doi: 10.3390/ma16196602.
S- and Se-based chalcogenide glasses are intrinsically metastable and exhibit a number of photo-induced effects unique to this class of materials, reversible photostructural changes and photo-induced anisotropy being major examples. These effects are usually interpreted in terms of the formation of valence alternation pairs and 'wrong' bonds. In this work, using density functional theory simulations, we demonstrate for the case example of As2S3 that a strong decrease in the optical band gap can be achieved if a polymorphic transformation of the local structure from orpiment to that of tetradymite takes place. For the formation of the latter, the presence of lone-pair electrons in near-linear atomic configurations is crucial. Our results represent a novel approach to understanding the photo-induced structural changes in chalcogenide glasses as being due to the presence of polymorphism, and will lead to their wider use in various photonic devices.
基于硫（S）和硒（Se）的硫属化物玻璃本质上是亚稳态的，并且表现出这类材料特有的许多光致效应，主要例子是可逆的光结构变化和光致各向异性。这些效应通常根据价态交替对和“错误”键的形成来解释。在这项工作中，我们使用密度泛函理论模拟，以As2S3为例证明，如果局部结构从雌黄多晶型转变为辉碲铋矿型，光学带隙会大幅降低。对于后者的形成，近线性原子构型中孤对电子的存在至关重要。我们的结果代表了一种理解硫属化物玻璃中光致结构变化归因于多晶型存在的新方法，并将导致它们在各种光子器件中得到更广泛的应用。
