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Title: Effect of carrier density and valence states on superconductivity of oxygen annealed Fe{sub 1.06}Te{sub 0.6}Se{sub 0.4} single crystals

The variations of carrier density and valence states in oxygen annealed Fe{sub 1.06}Te{sub 0.6}Se{sub 0.4} single crystals were studied systematically. It was found that the carrier density n{sub H} increases after oxygen annealing by Hall coefficient measurements. The X-ray photoelectron spectroscopy experiments reveal that the oxygen annealing changes Fe{sup 0} and Te{sup 0} states to Fe{sup 2+/3+} and Te{sup 4+}, respectively, while the valence variation of Se is negligible. Our results indicate that the improvement of superconductivity, such as the zero resistance transition temperature T{sub c}{sup zero}, shielding and Meissner fraction value 4πχ and upper critical field H{sub c2}, could be closely related to the proper manipulation of n{sub H} and the valence states by oxygen annealing in the system.
Authors:
; ; ; ; ;  [1]
  1. Hefei National Laboratory for Physical Sciences at Microscale, Department of Physics, University of Science and Technology of China, Hefei 230026 (China)
Publication Date:
OSTI Identifier:
22257793
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 114; Journal Issue: 18; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ANNEALING; CARRIER DENSITY; CRITICAL FIELD; HIGH ROOMS; IRON IONS; MONOCRYSTALS; OXYGEN; SUPERCONDUCTIVITY; TELLURIUM IONS; TRANSITION TEMPERATURE; VALENCE; X-RAY PHOTOELECTRON SPECTROSCOPY