10.1021/ic400727g.s001 Jinggeng Zhao Jinggeng Zhao Haozhe Liu Haozhe Liu Lars Ehm Lars Ehm Dawei Dong Dawei Dong Zhiqiang Chen Zhiqiang Chen Qingqing Liu Qingqing Liu Wanzheng Hu Wanzheng Hu Nanlin Wang Nanlin Wang Changqing Jin Changqing Jin Pressure-Induced Phase Transitions and Correlation between Structure and Superconductivity in Iron-Based Superconductor Ce(O<sub>0.84</sub>F<sub>0.16</sub>)FeAs American Chemical Society 2013 13.9 GPa charge reservoir layer 33.8 GPa transition region 54.9 GPa bond distances structure evolution pressure dependences structure analysis superconducting transition temperature Tc lanthanide cations superconductivity changes Ce room temperature isostructural phase transition 19.9 GPa 2013-07-15 00:00:00 Journal contribution https://acs.figshare.com/articles/journal_contribution/Pressure_Induced_Phase_Transitions_and_Correlation_between_Structure_and_Superconductivity_in_Iron_Based_Superconductor_Ce_O_sub_0_84_sub_F_sub_0_16_sub_FeAs/2396314 High-pressure angle-dispersive X-ray diffraction experiments on iron-based superconductor Ce­(O<sub>0.84</sub>F<sub>0.16</sub>)­FeAs were performed up to 54.9 GPa at room temperature. A tetragonal to tetragonal isostructural phase transition starts at about 13.9 GPa, and a new high-pressure phase has been found above 33.8 GPa. At pressures above 19.9 GPa, Ce­(O<sub>0.84</sub>F<sub>0.16</sub>)­FeAs completely transforms to a high-pressure tetragonal phase, which remains in the same tetragonal structure with a larger <i>a</i>-axis and smaller <i>c</i>-axis than those of the low-pressure tetragonal phase. The structure analysis shows a discontinuity in the pressure dependences of the Fe–As and Ce–(O, F) bond distances, as well as the As–Fe–As and Ce–(O, F)–Ce bond angles in the transition region, which correlates with the change in <i>T</i><sub>c</sub> of this compound upon compression. The isostructural phase transition in Ce­(O<sub>0.84</sub>F<sub>0.16</sub>)­FeAs leads to a drastic drop in the superconducting transition temperature <i>T</i><sub>c</sub> and restricts the superconductivity at low temperature. For the 1111-type iron-based superconductors, the structure evolution and following superconductivity changes under compression are related to the radius of lanthanide cations in the charge reservoir layer.