title: Friedel-like oscillations from interstitial iron in superconducting Fe(1+y)Te0.62Se0.38.
abstract: Using polarized and unpolarized neutron scattering, we show that interstitial Fe in superconducting Fe(1+y)Te(1-x)Se(x) induces a magnetic Friedel-like oscillation that diffracts at Q⊥=(1/2 0) and involves >50 neighboring Fe sites. The interstitial >2μ(B) moment is surrounded by compensating ferromagnetic four-spin clusters that may seed double stripe ordering in Fe(1+y)Te. A semimetallic five-band model with (1/2 1/2) Fermi surface nesting and fourfold symmetric superexchange between interstitial Fe and two in-plane nearest neighbors largely accounts for the observed diffraction.
authors.affiliation: Institute for Quantum Matter and Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, USA.
authors.forename: V
authors.initials: V
authors.lastname: Thampy
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authors.lastname: Kang
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authors.lastname: Rodriguez-Rivera
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authors.lastname: Bao
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authors.lastname: Savici
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authors.lastname: Hu
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authors.lastname: Liu
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authors.lastname: Qian
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authors.lastname: Fobes
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authors.lastname: Mao
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authors.lastname: Fu
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authors.lastname: Chen
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authors.lastname: Ye
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authors.lastname: Erwin
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authors.lastname: Gentile
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authors.lastname: Tesanovic
authors.forename: C
authors.initials: C
authors.lastname: Broholm