Two-dimensional Cs-vacancy superstructure in iron-based superconductor Cs0.8Fe1.6Se2

D. G. Porter; E. Cemal; D. J. Voneshen; K. Refson; M. J. Gutmann; A. Bombardi; A. T. Boothroyd; A. Krzton-Maziopa; E. Pomjakushina; K. Conder; J. P. Goff

doi:10.1103/PhysRevB.91.144114

Two-dimensional Cs-vacancy superstructure in iron-based superconductor Cs0.8Fe1.6Se2

D. G. Porter, E. Cemal, D. J. Voneshen, K. Refson, M. J. Gutmann, A. Bombardi, A. T. Boothroyd, A. Krzton-Maziopa, E. Pomjakushina, K. Conder, J. P. Goff

DOI 10.1103/PhysRevB.91.144114 · Physical Review B

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Abstract

Single crystal neutron diffraction is combined with synchrotron x-ray scattering to identify the different superlattice phases present in Cs0.8Fe1.6Se2. A combination of single crystal refinements and first principles modeling are used to provide structural solutions for the 5×5 and 2×2 superlattice phases. The 5×5 superlattice structure is predominantly composed of ordered Fe vacancies and Fe distortions, whereas the 2×2 superlattice is composed of ordered Cs vacancies. The Cs vacancies only order within the plane, causing Bragg rods in reciprocal space. By mapping x-ray diffraction measurements with narrow spatial resolution over the surface of the sample, the structural domain pattern was determined, consistent with the notion of a majority antiferromagnetic 5×5 phase and a superconducting 2×2 phase.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
Cs0.8Fe1.6Se2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	30	Pressure not reported	unknown