Dopant clustering, electronic inhomogeneity, and vortex pinning in iron-based superconductors
Hudson, E. W.
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CitationSong, Can-Li, Yi Yin, Martin Zech, Tess Williams, Michael M. Yee, Gen-Fu Chen, Jian-Lin Luo, Nan-Lin Wang, E. W. Hudson, and Jennifer E. Hoffman. 2013. “Dopant Clustering, Electronic Inhomogeneity, and Vortex Pinning in Iron-Based Superconductors.” Phys. Rev. B 87 (21) (June): 214519.
AbstractWe use scanning tunneling microscopy to map the surface structure, nanoscale electronic inhomogeneity, and vitreous vortex phase in the hole-doped superconductor Sr0.75K0.25Fe2As2 with Tc=32 K. We find that the low-T cleaved surface is dominated by a half Sr/K termination with 1×2 ordering and ubiquitous superconducting gap, while patches of gapless, unreconstructed As termination appear rarely. The superconducting gap varies by σ/Δ¯=16% on a ∼3 nm length scale, with average 2Δ¯/kBTc=3.6 in the weak-coupling limit. The vortex core size provides a measure of the superconducting coherence length ξ=2.3 nm. We quantify the vortex lattice correlation length at 9 T in comparison to several iron-based superconductors. The comparison leads us to suggest the importance of dopant size mismatch as a cause of dopant clustering, electronic inhomogeneity, and strong vortex pinning.
Citable link to this pagehttp://nrs.harvard.edu/urn-3:HUL.InstRepos:12748089
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