Unconventional Mott Transition in KxFe2-ySe2

Abstract

Whether the newly discovered KxFe2-ySe2 systems are doped Mott or band insulators is key to how superconductivity emerges at lower temperature. With extant theoretical studies supporting conflicting scenarios, a more realistic approach is urgently called for. Here, we use LDA+DMFT to study this issue in KxFe2-ySe2. We find that the undoped KFe1.6Se2 system is a new kind of Mott-Kondo insulator (MKI). Electron doping this MKI drives a Mott transition to an orbital-selective non-Fermi liquid metal. Good agreement with spectral and transport responses supports our view, implying that superconductivity arises from a doped Mott insulator, as in the high-Tc cuprates.

4 pages, 5 figures

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Cited by in corpus (16)

• The Unexpected Properties of Alkali Metal Iron Selenide Superconductors
• Observation of Temperature-Induced Crossover to an Orbital-Selective Mott Phase in A${}_x$Fe${}_{2-y}$Se${}_2$ (A=K, Rb) Superconductors
• Orbital-selective Mott Phase in Multiorbital Models for Alkaline Iron Selenides K(1-x)Fe(2-y)Se2
• Fractional power-law behavior and its origin in iron-chalcogenide and ruthenate superconductors: Insights from first-principles calculations
• How correlated is the FeSe/SrTiO${}_3$ system ?
• The role of 245 phase in alkaline iron selenide superconductors revealed by high pressure studies
• Mott-Kondo Insulator Behavior in the Iron Oxychalcogenides
• Heterostructural one-unit-cell FeSe/SrTiO3: from high-temperature superconductivity to topological states
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• Microscopic description of insulator-metal transition in high-pressure oxygen
• Insulating and metallic spin glass in K${}_x$Fe${}_{2-\delta -y}$Ni${}_y$Se${}_2$ (0.06 $\le$ $y$ $\le$ 1.44) single crystals
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• Temperature and doping dependence of normal state spectral properties in a two-orbital model for ferropnictides
• On the bad metallicity and phase diagrams of Fe${}_{1+\delta }X$ ($X$ =Te, Se, S, solid solutions): an electrical resistivity study