Unexpected weak spatial variation of local density of sates induced by individual Co impurity atoms in Na(Fe{1-x}Cox)As as revealed by scanning tunneling spectroscopy

Abstract

We use spatially resolved scanning tunneling spectroscopy in Na(Fe{1-x}Cox)As to investigate the impurity effect induced by Co dopants. The Co impurities are successfully identified, and the spatial distributions of local density of state at different energies around these impurities are investigated. It is found that the spectrum shows negligible spatial variation at different positions near the Co impurity, although there is a continuum of the in-gap states which lifts the zero-bias conductance to a finite value. Our results put constraints on the S+- and S++ models and sharpen the debate on the role of scattering potentials induced by the Co dopants.

8 pages, 10 figures

References in corpus (15)

• Unconventional pairing originating from disconnected Fermi surfaces in superconducting LaFeAsO${}_{1-x}$F${}_x$}
• The Kernel Polynomial Method
• Strong Correlations and Magnetic Frustration in the High Tc Iron Pnictides
• Pairing Symmetry in a Two-Orbital Exchange Coupling Model of Oxypnictides
• Scanning Tunneling Spectroscopy and Vortex Imaging in the Iron-Pnictide Superconductor BaFe${}_{1.8}$Co${}_{0.2}$As${}_2$
• Where Are the Extra d Electrons in Transition-Metal Substituted Fe Pnictides?
• Superfluid density of the $\pm$s-wave state for the iron-based superconductors
• Momentum-dependence of Superconducting Gap, strong-coupling dispersion Kink, and tightly bound Cooper pairs in the high-Tc (Sr,Ba)1-x(K,Na)xFe2As2 superconductors
• Observation of Lattice and Andreev Bound States of Vortices in Ba0.6K0.4Fe2As2 Single Crystals with Scanning Tunneling Microscopy/Spectroscopy
• The cleavage surface of the BaFe_(2-x)Co_(x)As_(2) and Fe_(y)Se_(1-x)Te_(x) superconductors: from diversity to simplicity
• Nanoscale superconducting gap variations, strong coupling signatures and lack of phase separation in optimally doped BaFe1.86Co0.14As2
• Probing the role of Co substitution in the electronic structure of iron-pnictides
• Effects of cobalt doping and three-dimensionality in $BaF{e}_{2}A{s}_2$
• Measurement of a Sign-Changing Two-Gap Superconducting Phase in Electron-Doped Ba(Fe_{1-x}Co_x)_2As_2 Single Crystals using Scanning Tunneling Spectroscopy
• Single Impurity Problem in Iron-Pnictide Superconductors

Cited by in corpus (1)

• Evolution from unconventional spin density wave to superconductivity and a novel gap-like phase in NaFe1-xCoxAs