Comparing the anomalous phonons in Fe(Te,Se) and (Fe,Ni)(Te,Se) via neutron scattering

ORAL

Abstract

We studied the anomalous acoustic-type phonons in the Fe(Te,Se) iron-based superconductor family that arise from the (100) Bragg peak, which is forbidden according to the reported crystal structure for these materials. Inelastic neutron scattering was performed on superconducting and non-superconducting crystals of various compositions. The (100) phonons were much weaker in a non-superconducting nickel-doped crystal than in a superconducting crystal with similar selenium fraction, but comparison with another non-superconducting crystal suggests the difference is not simply related to superconductivity. This composition dependence was observed for both transverse and longitudinal phonons. The temperature dependences of the (100) phonons resembled those of conventional phonons. We will discuss these results and possible explanations for the relation between composition and lattice dynamics in this system.

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Authors

  • J. A. Schneeloch

    Brookhaven National Laboratory, Brookhaven National Lab, Brookhaven National Lab, Upton, New York 11973, USA

  • Zhijun Xu

    University of California, Berkeley, UC Berkeley

  • G. D. Gu

    Brookhaven National Laboratory, Brookhaven Natl Lab, Brookhaven national laboratory, Brookhaven National Lab, Brookhaven National Lab, Upton, NY, Brookhaven National Laboratory, NY 11973, Brookhaven National Lab, Upton, New York 11973, USA

  • Igor Zaliznyak

    Brookhaven National Laboratory

  • Barry Winn

    Oak Ridge National Laboratory

  • J. A. Rodriguez-Rivera

    National Institute of Standards and Technology, NIST, NIST and Univ of Maryland, NIST Center for Neutron Research

  • Robert Birgeneau

    University of California, Berkeley

  • Guangyong Xu

    Brookhaven National Laboratory

  • John Tranquada

    Brookhaven National Laboratory, Brookhaven Natl Lab