Giant Pressure-Driven Lattice Collapse Coupled with Intermetallic Bonding and Spin-State Transition in Manganese Chalcogenides

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• 作者：Dr. Yonggang Wang ; Dr. Ligang Bai ; Ting Wen ; Dr. Liuxiang Yang ; Huiyang Gou ; Yuming Xiao ; Paul Chow ; Prof. Michael Pravica ; Wenge Yang and Prof. Yusheng Zhao
• 刊名：Angewandte Chemie
• 出版年：2016
• 出版时间：August 22, 2016
• 年：2016
• 卷：128
• 期：35
• 页码：10506-10509
• 全文大小：1398K
• ISSN：1521-3757

文摘

Materials with an abrupt volume collapse of more than 20 % during a pressure-induced phase transition are rarely reported. In such an intriguing phenomenon, the lattice may be coupled with dramatic changes of orbital and/or the spin-state of the transition metal. A combined in situ crystallography and electron spin-state study to probe the mechanism of the pressure-driven lattice collapse in MnS and MnSe is presented. Both materials exhibit a rocksalt-to-MnP phase transition under compression with ca. 22 % unit-cell volume changes, which was found to be coupled with the Mn²⁺(d⁵) spin-state transition from S=5/2 to S=1/2 and the formation of Mn−Mn intermetallic bonds as supported by the metallic transport behavior of their high-pressure phases. Our results reveal the mutual relationship between pressure-driven lattice collapse and the orbital/spin-state of Mn²⁺ in manganese chalcogenides and also provide deeper insights toward the exploration of new metastable phases with exceptional functionalities.