Strong similarities between the local electronic structure of insulating iron pnictide and lightly doped cuprate

Abstract

One of the major puzzles regarding unconventional superconductivity is how some of the most interesting superconductors are related to an insulating phase that lies in close proximity. Here we report scanning tunneling microscopy studies of the local electronic structure of Cu doped NaFeAs across the superconductor to insulator transition. We find that in the highly insulating regime the electronic spectrum develops an energy gap with diminishing density of state at the Fermi level. The overall lineshape and strong spatial variations of the spectra are strikingly similar to that of lightly doped cuprates close to the parent Mott insulator. We propose that the suppression of itinerant electron state and strong impurity potential induced by Cu dopants lead to this insulating iron pnictide.

6 figures, to appear in Phys. Rev. X

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Cited by in corpus (10)

• NaFe${}_{0.56}$Cu${}_{0.44}$As: A pnictide insulating phase induced by on-site Coulomb interaction
• Phase diagram and neutron spin resonance of superconducting NaFe${}_{1-x}$Cu${}_x$As
• Local breaking of four-fold rotational symmetry by short-range magnetic order in heavily overdoped Ba(Fe${}_{1-x}$Cu${}_x$)${}_2$As${}_2$
• Orbital-selective coherence-incoherence crossover and metal-insulator transition in Cu-doped NaFeAs
• Cu doping effects on the electronic structure of Fe1-xCuxSe
• Electronic and spin dynamics in the insulating iron pnictide NaFe${}_{0.5}$Cu${}_{0.5}$As
• Toward the Mott state with Magnetic Cluster Formation in Heavily Cu-Doped NaFe${}_{1-x}$Cu${}_x$As
• Spin dynamics in NaFeAs and NaFe${}_{0.53}$Cu${}_{0.47}$As probed by resonant inelastic X-ray scattering
• Enhanced low-energy magnetic excitations evidencing the Cu-induced localization in an Fe-based superconductor Fe${}_{0.98}$Te${}_{0.5}$Se${}_{0.5}$
• Quasi-one-dimensional spin excitations in the iron pnictide NaFe${}_{0.53}$Cu${}_{0.47}$As