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Title: Pressure-Induced Isostructural Phase Transition and Correlation of FeAs Coordination with the Superconducting Properties of 111-Type Na1-xFeAs

Journal Article · · Journal of the American Chemical Society
DOI:https://doi.org/10.1021/ja2009949· OSTI ID:1041902

The effect of pressure on the crystalline structure and superconducting transition temperature (T{sub c}) of the 111-type Na{sub 1-x}FeAs system using in situ high-pressure synchrotron X-ray powder diffraction and diamond anvil cell techniques is studied. A pressure-induced tetragonal to tetragonal isostructural phase transition was found. The systematic evolution of the FeAs{sub 4} tetrahedron as a function of pressure based on Rietveld refinements on the powder X-ray diffraction patterns was obtained. The nonmonotonic T{sub c}(P) behavior of Na{sub 1-x}FeAs is found to correlate with the anomalies of the distance between the anion (As) and the iron layer as well as the bond angle of As-Fe-As for the two tetragonal phases. This behavior provides the key structural information in understanding the origin of the pressure dependence of T{sub c} for 111-type iron pnictide superconductors. A pressure-induced structural phase transition is also observed at 20 GPa.

Research Organization:
Brookhaven National Lab. (BNL), Upton, NY (United States)
Sponsoring Organization:
USDOE SC OFFICE OF SCIENCE (SC)
DOE Contract Number:
DE-AC02-98CH10886
OSTI ID:
1041902
Report Number(s):
BNL-97580-2012-JA; JACSAT; TRN: US201212%%313
Journal Information:
Journal of the American Chemical Society, Vol. 133, Issue 20; ISSN 0002-7863
Country of Publication:
United States
Language:
English