title: Fermi surface topology and low-lying quasiparticle dynamics of parent Fe1+xTe/Se superconductor.
abstract: We report the first photoemission study of Fe1+xTe-the host compound of the newly discovered iron-chalcogenide superconductors (maximum Tc approximately 27 K). Our results reveal a pair of nearly electron-hole compensated Fermi pockets, strong Fermi velocity renormalization, and an absence of a spin-density-wave gap. A shadow hole pocket is observed at the "X" point of the Brillouin zone which is consistent with a long-range ordered magnetostructural ground state. No signature of Fermi surface nesting instability associated with Q=(pi/2,pi/2) is observed. Our results collectively reveal that the Fe1+xTe series is different from the undoped phases of the high Tc pnictides and likely harbor an unusual mechanism for superconductivity and magnetic order.
authors: Joseph Henry Laboratories of Physics, Department of Physics, Princeton Center for Complex Materials, Princeton University, Princeton, New Jersey 08544, USA.
authors: Y
authors: Y
authors: Xia
authors: D
authors: D
authors: Qian
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authors: Wray
authors: D
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authors: Hsieh
authors: G F
authors: GF
authors: Chen
authors: J L
authors: JL
authors: Luo
authors: N L
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authors: Wang
authors: M Z
authors: MZ
authors: Hasan