Doping dependence of the anisotropic quasiparticle interference in NaFe1-xCoxAs iron-based superconductors

Abstract

We use scanning tunneling microscopy to investigate the doping dependence of quasiparticle interference (QPI) in NaFe1-xCoxAs iron-based superconductors. The goal is to study the relation between nematic fluctuations and Cooper pairing. In the parent and underdoped compounds, where four-fold rotational symmetry is broken macroscopically, the QPI patterns reveal strong rotational anisotropy. At optimal doping, however, the QPI patterns are always four-fold symmetric. We argue this implies small nematic susceptibility and hence insignificant nematic fluctuation in optimally doped iron pnictides. Since Tc is the highest this suggests nematic fluctuation is not a prerequistite for strong Cooper pairing.

4 figures, to appear in Physical Review Letters

References in corpus (10)

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• Orbital Order and Spontaneous Orthorhombicity in Iron Pnictides
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Cited by in corpus (10)

• Spin fluctuations in iron pnictides and chalcogenides: From antiferromagnetism to superconductivity
• Evidence of nematic order and nodal superconducting gap along [110] direction in RbFe2As2
• Nematic crossover in BaFe${}_2$As${}_2$ under uniaxial stress
• Bounds on Nanoscale Nematicity in Single-Layer FeSe/SrTiO${}_3$
• Simultaneous Vanishing of the Nematic Electronic State and the Structural Orthorhombicity in NaFe${}_{1-x}$Co${}_x$As Single Crystals
• Quasiparticle Interference in Fe-based Superconductors Based on a Five-Orbital Tight-Binding Model
• Quasiparticle scattering interference in iron pnictides: A probe of the origin of nematicity
• Interplay between nematic fluctuation and superconductivity in the two-orbital Hubbard model: A quantum Monte Carlo study
• The influence of the structural transition on magnetic fluctuations in NaFeAs
• Anisotropic Electronic Mobilities in the Nematic State of the Parent Phase NaFeAs