Impact of Iron-site defects on Superconductivity in LiFeAs

Abstract

In conventional s-wave superconductors, only magnetic impurities exhibit impurity bound states, whereas for an s+- order parameter they can occur for both magnetic and non-magnetic impurities. Impurity bound states in superconductors can thus provide important insight into the order parameter. Here, we present a combined experimental and theoretical study of native and engineered iron-site defects in LiFeAs. Detailed comparison of tunneling spectra measured on impurities with spin fluctuation theory reveals a continuous evolution from negligible impurity bound state features for weaker scattering potential to clearly detectable states for somewhat stronger scattering potentials. All bound states for these intermediate strength potentials are pinned at or close to the gap edge of the smaller gap, a phenomenon that we explain and ascribe to multi-orbital physics.

5 pages, 4 figures

References in corpus (5)

• Anisotropic Energy Gaps of Iron-based Superconductivity from Intra-band Quasiparticle Interference in LiFeAs
• Interpretation of scanning tunneling quasiparticle interference and impurity states in cuprates
• Scanning tunneling spectroscopy of superconducting LiFeAs single crystals: Evidence for two nodeless energy gaps and coupling to a bosonic mode
• Dumbbell Defects in FeSe Films: A Scanning Tunneling Microscopy and First-Principles Investigation
• 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

Cited by in corpus (9)

• On the Remarkable Superconductivity of FeSe and its Close Cousins
• Unconventional density waves and superconductivities in Fe-based superconductors and other strongly correlated electron systems
• Universality of scanning tunneling microscopy in cuprate superconductors
• Towards a quantitative description of tunneling conductance of superconductors: application to LiFeAs
• Quantum phase transition of correlated iron-based superconductivity in LiFe${}_{1-x}$Co${}_x$As
• Impurity-induced bound states inside the superconducting gap of FeSe
• Direct visualization of phase separation between superconducting and nematic domains in Co-doped CaFe2As2 close to a first order phase transition
• Electronic Theory for Scanning Tunneling Microscopy Spectra in Infinite-Layer Nickelate Superconductors
• Local signatures of altermagnetism