L-dependence of low energy spin excitations in FeTe/Se superconductors

ORAL

Abstract

We will present neutron scattering measurements on low energy magnetic excitations from FeTe$_{1-x}$Se$_x$ (``11'' system) samples. Our work shows that the low energy magnetic excitations are dominated by 2D correlations in the superconducting (SC) compound at low temperature, with the L-dependence well described by the Fe magnetic form factor. However, at temperatures much higher than T$_C$, the magnetic excitations become more three-dimensional with a clear change in the L-dependence. The low energy magnetic excitations from non-superconducting (NSC) samples, on the other hand, always exhibit three-dimensional features for the entire temperature range of our measurements. Our results suggest that in additional to in-plane correlations, the inter-plane spin correlations are also coupled to the superconducting properties in the ``11'' system.

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Authors

  • Guangyong Xu

    Brookhaven National Laboratory, Comdensed Matter Physics & materials Science Department, Brookhaven national laboratory

  • zhijun xu

    NIST Center for Neutron Research, University of Maryland and NIST Center for Neutron Research

  • John Schneeloch

    Stonybrook University, Comdensed Matter Physics \& materials Science Department, Brookhaven national laboratory, Brookhaven Natl Lab, Brookhaven National Laboratory

  • Jinsheng Wen

    Nanjing University

  • Barry Winn

    Oak Ridge National Laboratory

  • Yang Zhao

    NIST Center for Neutron Research

  • Robert Birgeneau

    University of California, Berkeley, UC Berkeley, University of California Berkeley

  • Genda Gu

    Brookhaven National Laboratory, Comdensed Matter Physics \& materials Science Department, Brookhaven national laboratory, Brookhaven Natl Lab

  • John Tranquada

    Brookhaven National Laboratory, Comdensed Matter Physics \& materials Science Department, Brookhaven national laboratory, Brookhaven Natl Lab