Mercury Sulfide Dimorphism in Thioarsenate Glasses

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• 作者：M. Kassem ; A. Sokolov ; A. Cuisset ; T. Usuki ; S. Khaoulani ; P. Masselin ; D. Le Coq ; J. C. Neuefeind ; M. Feygenson ; A. C. Hannon ; C. J. Benmore ; E. Bychkov
• 刊名：Journal of Physical Chemistry B
• 出版年：2016
• 出版时间：June 16, 2016
• 年：2016
• 卷：120
• 期：23
• 页码：5278-5290
• 全文大小：784K
• 年卷期：0
• ISSN：1520-5207

文摘

Crystalline mercury sulfide exists in two drastically different polymorphic forms in different domains of the P,T-diagram: red chain-like insulator α-HgS, stable below 344 °C, and black tetrahedral narrow-band semiconductor β-HgS, stable at higher temperatures. Using pulsed neutron and high-energy X-ray diffraction, we show that these two mercury bonding patterns are present simultaneously in mercury thioarsenate glasses HgS–As₂S₃. The population and interconnectivity of chain-like and tetrahedral dimorphous forms determine both the structural features and fundamental glass properties (thermal, electronic, etc.). DFT simulations of mercury species and RMC modeling of high-resolution diffraction data provide additional details on local Hg environment and connectivity implying the (HgS_2/2)_m oligomeric chains (1 ≤ m ≤ 6) are acting as a network former while the HgS_4/4-related mixed agglomerated units behave as a modifier.