Theoretical Prediction and Experimental Confirmation of Unusual Ternary Ordered Semiconductor Compounds in Sr–Pb–S System

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• 作者：Shiqiang Hao ; Li-Dong Zhao ; Chang-Qiang Chen ; Vinayak P. Dravid ; Mercouri G. Kanatzidis ; Christopher M. Wolverton
• 刊名：Journal of the American Chemical Society
• 出版年：2014
• 出版时间：January 29, 2014
• 年：2014
• 卷：136
• 期：4
• 页码：1628-1635
• 全文大小：651K
• ISSN：1520-5126

文摘

We examine the thermodynamics of phase separation and ordering in the ternary Ca_xPb_1鈥?i>xS and Sr_xPb_1鈥?i>xS systems by density-functional theory combined with a cluster expansion and Monte Carlo simulations. Similar to most other ternary III鈥揤 or IV鈥揤I semiconductor alloys, we find that bulk phase separation is thermodynamically preferred for PbS鈥揅aS. However, we predict the surprising existence of stable, ordered ternary compounds in the PbS鈥揝rS system. These phases are previously unreported ordered rocksalt-based compounds: SrPb₃S₄, SrPbS₂, and Sr₃PbS₄. The stability of these predicted ordered phases is confirmed by transmission electron microscopy observations and band gap measurements. We believe this work paves the way for a combined theory-experiment approach to decipher complex phase relations in multicomponent chalcogenide systems.