Campus Units
Physics and Astronomy, Ames Laboratory
Document Type
Article
Publication Version
Accepted Manuscript
Publication Date
4-2013
Journal or Book Title
Nature Physics
Volume
9
First Page
220
Last Page
224
DOI
10.1038/nphys2544
Abstract
Iron-based high-temperature superconductivity develops when the ‘parent’ antiferromagnetic/orthorhombic phase is suppressed, typically by introduction of dopant atoms1. But their impact on atomic-scale electronic structure, although in theory rather complex2,3,4,5,6,7,8,9,10,11,12,13, is unknown experimentally. What is known is that a strong transport anisotropy14,15,16,17,18,19,20,21,22,23,24,25 with its resistivity maximum along the crystal b axis14,15,16,17,18,19,20,21,22,23,24,25, develops with increasing concentration of dopant atoms14,20,21,22,23,24,25; this ‘nematicity’vanishes when the parent phase disappears near the maximum superconducting Tc. The interplay between the electronic structure surrounding each dopant atom, quasiparticle scattering therefrom and the transport nematicity has therefore become a pivotal focus7,8,12,22,23 of research into these materials. Here, by directly visualizing the atomic-scale electronic structure, we show that substituting Co for Fe atoms in underdoped Ca(Fe1−xCox)2As2 generates a dense population of identical anisotropic impurity states. Each is ∼ 8 Fe–Fe unit cells in length, and all are distributed randomly but aligned with the antiferromagnetic a axis. By imaging their surrounding interference patterns, we further demonstrate that these impurity states scatter quasiparticles in a highly anisotropic manner, with the maximum scattering rate concentrated along the b axis. These data provide direct support for the recent proposals7,8,12,22,23 that it is primarily anisotropic scattering by dopant-induced impurity states that generates the transport nematicity; they also yield simple explanations for the enhancement of the nematicity proportional to the dopant density14,20,21,22,23,24,25 and for the occurrence of the highest resistivity along the b axis14,15,16,17,18,19,20,21,22,23,24,25.
Copyright Owner
Springer Nature
Copyright Date
2013
Language
en
File Format
application/pdf
Recommended Citation
Allan, M. P.; Chuang, T.-M.; Massee, F.; Xie, Yang; Ni, Ni; Bud’ko, Sergey L.; Boebinger, G. S.; Wang, Q.; Dessau, D. S.; Canfield, Paul C.; Golden, M. S.; and Davis, J. C., "Anisotropic impurity states, quasiparticle scattering and nematic transport in underdoped Ca(Fe1−xCox)2As2" (2013). Physics and Astronomy Publications. 630.
https://lib.dr.iastate.edu/physastro_pubs/630
Comments
This is a manuscript of an article published as Allan, M. P., T.-M. Chuang, F. Massee, Yang Xie, Ni Ni, S. L. Bud’ko, G. S. Boebinger, Q. Wang, D. S. Dessau, P. C. Canfield, M. S. Golden, and J. C. Davis. "Anisotropic impurity states, quasiparticle scattering and nematic transport in underdoped Ca(Fe1-xCox)(2)As-2." Nature Physics 9, no. 4 (2013): 220-224. DOI: 10.1038/nphys2544. Posted with permission.