Pressure-Driven Cooperative Spin-Crossover, Large-Volume Collapse, and Semiconductor-to-Metal Transition in Manganese(II) Honeycomb Lattices

详细信息    查看全文

• 作者：Yonggang Wang ; Zhengyang Zhou ; Ting Wen ; Yannan Zhou ; Nana Li ; Fei Han ; Yuming Xiao ; Paul Chow ; Junliang Sun ; Michael Pravica ; Andrew L. Cornelius ; Wenge Yang ; Yusheng Zhao
• 刊名：Journal of the American Chemical Society
• 出版年：2016
• 出版时间：December 7, 2016
• 年：2016
• 卷：138
• 期：48
• 页码：15751-15757
• 全文大小：539K
• ISSN：1520-5126

文摘

Spin-crossover (SCO) is generally regarded as a spectacular molecular magnetism in 3d⁴–3d⁷ metal complexes and holds great promise for various applications such as memory, displays, and sensors. In particular, SCO materials can be multifunctional when a classical light- or temperature-induced SCO occurs along with other cooperative structural and/or electrical transport alterations. However, such a cooperative SCO has rarely been observed in condensed matter under hydrostatic pressure (an alternative external stimulus to light or temperature), probably due to the lack of synergy between metal neighbors under compression. Here, we report the observation of a pressure-driven, cooperative SCO in the two-dimensional (2D) honeycomb antiferromagnets MnPS₃ and MnPSe₃ at room temperature. Applying pressure to this confined 2D system leads to a dramatic magnetic moment collapse of Mn²⁺ (d⁵) from S = 5/2 to S = 1/2. Significantly, a number of collective phenomena were observed along with the SCO, including a large lattice collapse (∼20% in volume), the formation of metallic bonding, and a semiconductor-to-metal transition. Experimental evidence shows that all of these events occur in the honeycomb lattice, indicating a strongly cooperative mechanism that facilitates the occurrence of the abrupt pressure-driven SCO. We believe that the observation of this cooperative pressure-driven SCO in a 2D system can provide a rare model for theoretical investigations and lead to the discovery of more pressure-responsive multifunctional materials.