Zhang Han, Wu Xiaozhi, Li Dandan, Jin Shifeng, Chen Xiao, Zhang Tao, Lin Zhiping, Shen Shijie, Yuan Duanduan, Chen Xiaolong
Research & Development Center for Functional Crystals, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.
J Phys Condens Matter. 2016 Apr 13;28(14):145701. doi: 10.1088/0953-8984/28/14/145701. Epub 2016 Mar 11.
We report here the first layered iron oxychalcogenide Ca2O3Fe2.6S2 that contains both planar Ca2FeO2 and Fe2OS2 layers with the shortest Fe-Fe bond length. This compound is a narrow band gap (~0.073 eV) Mott insulator. The observed antiferromagnetic (AFM) transition at 77 K is due to the ordered Fe vacancies, which can be suppressed by partial substitution of Se for S. We show that the vacancy-free phase Ca2O3Fe3S2 may become a metal with moderate electron correlation comparable to the parent compound LaOFeAs of corresponding superconductors. Our results imply that iron oxychalcogenide can be converted from an AFM Mott insulator into a bad metal like iron pnictides through Fe-Fe bond length shrinking.
