Two spatially separated phases in semiconductingRb0.8Fe1.5S2

2014/08/05 by Meng Wang, Wei Tian, P. Valdivia +5 · 19 citations
Chemistry · Materials Science · Physics and Astronomy · #Antiferromagnetism #Chemistry #Condensed matter physics #Crystal structure #Crystallography #Iron-based superconductors research #Isostructural #Materials science #Neutron diffraction #Order (exchange) #Phase (matter) #Phase transition #Physics #Physics of Superconductivity and Magnetism #Superconductivity #Vacancy defect #cond-mat.supr-con

paper · pdf · doi:10.1103/physrevb.90.125148

published in Physical Review B 90(12) (American Physical Society) · 7 pages, 5 figures

arxiv created 2014/08/05 · openalex publication_date 2014/09/26 · arxiv updated 2014/09/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/06

Abstract

We report neutron scattering and transport measurements on semiconducting Rb_0.8Fe_1.5S₂, a compound isostructural and isoelectronic to the well-studied A_0.8Fe_ySe₂(A=K,\phantom\rule0.16em0exRb,\phantom\rule0.16em0exCs,\phantom\rule0.16em0exTl/K) superconducting systems. Both resistivity and dc susceptibility measurements reveal a magnetic phase transition at T=275\phantom\rule4pt0exK. Neutron diffraction studies show that the 275 K transition originates from a phase with rhombic iron vacancy order which exhibits an in-plane stripe antiferromagnetic ordering below 275 K. In addition, the stripe antiferromagnetic phase interdigitates mesoscopically with an ubiquitous phase with √(5)\ifmmode×\else\texttimes\fi√(5) iron vacancy order. This phase has a magnetic transition at T_N=425\phantom\rule4pt0exK and an iron vacancy order-disorder transition at T_S=600\phantom\rule4pt0exK. These two different structural phases are closely similar to those observed in the isomorphous Se materials. Based on the close similarities of the in-plane antiferromagnetic structures, moments sizes, and ordering temperatures in semiconducting Rb_0.8Fe_1.5S₂ and K_0.81Fe_1.58Se₂, we argue that the in-plane antiferromagnetic order arises from strong coupling between local moments. Superconductivity, previously observed in the A_0.8Fe_ySe_2\ensuremath-zS_z system, is absent in Rb_0.8Fe_1.5S₂, which has a semiconducting ground state. The implied relationship between stripe and block antiferromagnetism and superconductivity in these materials as well as a strategy for further investigation is discussed in this paper.

Citations

• The puzzle of high temperature superconductivity in layered iron pnictides and chalcogenides
• Competing orders and spin-density-wave instability in La(O 1−x F x )FeAs
• Evolution of correlation strength in KxFe2–ySe2superconductor doped with S