The role of 245 phase in alkaline iron selenide superconductors revealed by high pressure studies

Abstract

Here we show that a pressure of about 8 GPa suppresses both the vacancy order and the insulating phase, and a further increase of the pressure to about 18 GPa induces a second transition or crossover. No superconductivity has been found in compressed insulating 245 phase. The metallic phase in the intermediate pressure range has a distinct behavior in the transport property, which is also observed in the superconducting sample. We interpret this intermediate metal as an orbital selective Mott phase (OSMP). Our results suggest that the OSMP provides the physical pathway connecting the insulating and superconducting phases of these iron selenide materials.

arXiv comment32 pages, 4 figures

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• Orbital-selective Mott phase in multiorbital models for iron pnictides and chalcogenides
• Orbital selectivity in electron correlations and superconducting pairing of iron-based superconductors
• Orbital-dependent effects of electron correlations in microscopic models for iron-based superconductors
• Temperature dependence of iron local magnetic moment in phase-separated superconducting chalcogenide
• Origin of Pressure-induced Superconducting Phase in K${}_x$Fe${}_{2-y}$Se${}_2$ studied by Synchrotron X-ray Diffraction and Spectroscopy
• Effective Exchange Interactions for Bad Metals and Implications for Iron-based Superconductors
• Origin of the Higher-$T_\rm{c}$ Phase in the K${}_x$Fe${}_{2-y}$Se${}_2$ System
• Elucidating the magnetic and superconducting phases in the alkali metal intercalated iron chalcogenides
• Electron Correlation and Spin Dynamics in Iron Pnictides and Chalcogenides
• Orbital-selective bad metals due to Hund's rule and orbital anisotropy: a finite-temperature slave-spin treatment of the two-band Hubbard model
• Percolative Superconductivity in Electron-Doped Sr${}_{1-x}$Eu${}_x$CuO${}_{2+y}$ Films
• Tuning orbital-selective correlation effects in superconducting Rb${}_{0.75}$Fe${}_{1.6}$Se${}_{2-z}$S${}_z$
• Structure, superconductivity, and magnetism in Rb1-xFe1.6Se2-zSz
• Connection between ambient-pressure and pressure-induced superconducting phases in alkaline iron selenide superconductors
• Orbital-dependent electron dynamics in Fe-pnictide superconductors
• Photoinduced nematic state in FeSe${}_{0.4}$Te${}_{0.6}$
• On the bad metallicity and phase diagrams of Fe${}_{1+\delta }X$ ($X$ =Te, Se, S, solid solutions): an electrical resistivity study