title: Giant Pressure-Driven Lattice Collapse Coupled with Intermetallic Bonding and Spin-State Transition in Manganese Chalcogenides.
abstract: 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 Mn(2+) (d(5) ) 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 Mn(2+) in manganese chalcogenides and also provide deeper insights toward the exploration of new metastable phases with exceptional functionalities.
authors.affiliation: High Pressure Science and Engineering Center, University of Nevada Las Vegas, Las Vegas, NV, 89154, USA. yyggwang@gmail.com.|High Pressure Synergetic Consortium (HPSynC), Geophysical Laboratory, Carnegie Institution of Washington, Argonne, IL, 60439, USA. yyggwang@gmail.com.
authors.forename: Yonggang
authors.initials: Y
authors.lastname: Wang
authors.affiliation: High Pressure Collaborative Access Team (HPCAT), Geophysical Laboratory, Carnegie Institution of Washington, Argonne, IL, 60439, USA.
authors.forename: Ligang
authors.initials: L
authors.lastname: Bai
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: High Pressure Synergetic Consortium (HPSynC), Geophysical Laboratory, Carnegie Institution of Washington, Argonne, IL, 60439, USA.|Center for High Pressure Science and Technology Advanced Research (HPSTAR), Shanghai, 201203, China.
authors.forename: Liuxiang
authors.initials: L
authors.lastname: Yang
authors.affiliation: Center for High Pressure Science and Technology Advanced Research (HPSTAR), Shanghai, 201203, China.
authors.forename: Huiyang
authors.initials: H
authors.lastname: Gou
authors.affiliation: High Pressure Collaborative Access Team (HPCAT), Geophysical Laboratory, Carnegie Institution of Washington, Argonne, IL, 60439, USA.
authors.forename: Yuming
authors.initials: Y
authors.lastname: Xiao
authors.affiliation: High Pressure Collaborative Access Team (HPCAT), Geophysical Laboratory, Carnegie Institution of Washington, Argonne, IL, 60439, USA.
authors.forename: Paul
authors.initials: P
authors.lastname: Chow
authors.affiliation: High Pressure Science and Engineering Center, University of Nevada Las Vegas, Las Vegas, NV, 89154, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Pravica
authors.affiliation: High Pressure Synergetic Consortium (HPSynC), Geophysical Laboratory, Carnegie Institution of Washington, Argonne, IL, 60439, USA. yangwg@hpstar.ac.cn.|Center for High Pressure Science and Technology Advanced Research (HPSTAR), Shanghai, 201203, China. yangwg@hpstar.ac.cn.
authors.forename: Wenge
authors.initials: W
authors.lastname: Yang
authors.affiliation: High Pressure Science and Engineering Center, University of Nevada Las Vegas, Las Vegas, NV, 89154, USA. zhaoys@sustc.edu.cn.|Southern University of Science and Technology, Shenzhen, 518055, China. zhaoys@sustc.edu.cn.
authors.forename: Yusheng
authors.initials: Y
authors.lastname: Zhao
keywords: high pressure; intermetallic bonding; lattice collapse; manganese chalcogenides; spin-state transitions