title: Pressure-Driven Cooperative Spin-Crossover, Large-Volume Collapse, and Semiconductor-to-Metal Transition in Manganese(II) Honeycomb Lattices.
abstract: Spin-crossover (SCO) is generally regarded as a spectacular molecular magnetism in 3d4-3d7metal 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 MnPS3and MnPSe3at 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.
authors.affiliation: High Pressure Science and Engineering Center, University of Nevada , Las Vegas, Nevada 89154, United States.|HPSynC, Geophysical Laboratory, Carnegie Institution of Washington , Argonne, Illinois 60439, United States.
authors.forename: Yonggang
authors.initials: Y
authors.lastname: Wang
authors.affiliation: College of Chemistry and Molecular Engineering, Peking University , Beijing 100871, China.|College of Chemistry and Chemical Engineering, Chongqing University , Chongqing 400044, China.
authors.forename: Zhengyang
authors.initials: Z
authors.lastname: Zhou
authors.affiliation: Institute of Nanostructured Functional Materials, Huanghe Science and Technology College , Zhengzhou, Henan 450006, China.
authors.forename: Ting
authors.initials: T
authors.lastname: Wen
authors.affiliation: Institute of Nanostructured Functional Materials, Huanghe Science and Technology College , Zhengzhou, Henan 450006, China.
authors.forename: Yannan
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: Center for High Pressure Science and Technology Advanced Research (HPSTAR) , Pudong, Shanghai 201203, China.
authors.forename: Nana
authors.initials: N
authors.lastname: Li
authors.affiliation: HPSynC, Geophysical Laboratory, Carnegie Institution of Washington , Argonne, Illinois 60439, United States.|Center for High Pressure Science and Technology Advanced Research (HPSTAR) , Pudong, Shanghai 201203, China.|Center for the Study of Matter at Extreme Conditions, Department of Mechanical and Materials Engineering, Florida International University , Miami, Florida 33199, United States.
authors.forename: Fei
authors.initials: F
authors.lastname: Han
authors.affiliation: High Pressure Collaborative Access Team (HPCAT), Geophysical Laboratory, Carnegie Institution of Washington , Argonne, Illinois 60439, United States.
authors.forename: Yuming
authors.initials: Y
authors.lastname: Xiao
authors.affiliation: High Pressure Collaborative Access Team (HPCAT), Geophysical Laboratory, Carnegie Institution of Washington , Argonne, Illinois 60439, United States.
authors.forename: Paul
authors.initials: P
authors.lastname: Chow
authors.affiliation: College of Chemistry and Molecular Engineering, Peking University , Beijing 100871, China.
authors.forename: Junliang
authors.initials: J
authors.lastname: Sun
authors.affiliation: High Pressure Science and Engineering Center, University of Nevada , Las Vegas, Nevada 89154, United States.
authors.forename: Michael
authors.initials: M
authors.lastname: Pravica
authors.affiliation: High Pressure Science and Engineering Center, University of Nevada , Las Vegas, Nevada 89154, United States.
authors.forename: Andrew L
authors.initials: AL
authors.lastname: Cornelius
authors.affiliation: HPSynC, Geophysical Laboratory, Carnegie Institution of Washington , Argonne, Illinois 60439, United States.|Center for High Pressure Science and Technology Advanced Research (HPSTAR) , Pudong, Shanghai 201203, China.
authors.forename: Wenge
authors.initials: W
authors.lastname: Yang
authors.affiliation: High Pressure Science and Engineering Center, University of Nevada , Las Vegas, Nevada 89154, United States.|Southern University of Science and Technology , Shenzhen 518055, China.
authors.forename: Yusheng
authors.initials: Y
authors.lastname: Zhao