High Energy Spin Waves in CaFe2As2 Single Crystals

ORAL

Abstract

We present neutron scattering measurements of the magnetic excitations in single crystals of antiferromagnetic ordered CaFe2As2 (TN = 172 K), the parent compound of the newly discovered iron-arsenide based superconductors. The data reveals steeply dispersive and well-defined spin waves up to an energy of approximately 120 meV. The data below 120 meV can be fit to a Heisenberg model consisting of nearest-neighbor interactions (J1a, J1b and J1c) and next-nearest neighbor interaction (J2), yielding constraining values on the magnetic exchange coupling constants. Above 120 meV, the excitations appear weaker or strongly damped. Ab-initio calculations of the dynamic magnetic susceptibility show that the high energy behavior arises from the damping of itinerant spin waves by particle-hole excitations.

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Authors

  • Souleymane Diallo

    • Ames Laboratory, Ohio
    • Ames Laboratory

  • Vladimir Antropov

    • Ames Laboratory, Ames, IA, USA
    • Ames Laboratory, Ames, IA, 50011
    • Ames Laboratory
    • Ames Laboratory, Ames, IA, 50011, USA

  • Collin Broholm

    • Johns Hopkins University

  • Toby Perring

    • ISIS Neutron Facility

  • S.L. Bud'ko

    • Ames Laboratory and Iowa State University
    • Ames Laboratory and Physics Department and Astronomy, Iowa State University, Ames, IA
    • Ames Laboratory
    • Ames Laboratory, US DOE and Iowa State University
    • Ames Laboratory/Iowa State University
    • Ames Laboratory/Department of Physics and Astronomy
    • Ames laboratory

  • N. Ni

    • Ames Laboratory and Iowa State University
    • Ames Laboratory and Physics Department and Astronomy, Iowa State University, Ames, IA
    • Ames Lab / Iowa State University
    • Ames Laboratory, US DOE and Iowa State University
    • Iowa State University
    • Ames Laboratory/Department of Physics and Astronomy

  • P.C. Canfield

    • Ames Laboratory and Department of Physics and Astronomy, Iowa State Univeristy, Ames, Iowa 50011
    • Ames Laboratory and Iowa State University
    • Ames Laboratory and Physics Department and Astronomy, Iowa State University, Ames, IA
    • Ames Laboratory
    • Ames Laboratory, US DOE and Iowa State University
    • Ames Laboratory/Department of Physics and Astronomy
    • Ames Lab / Iowa State University
    • Ames Laboratory/Iowa State University

  • Andreas Kreyssig

    • kreyssig@ameslab.gov

  • Alan Goldman

    • Ames Laboratory and Physics Department and Astronomy, Iowa State University, Ames, IA
    • Ames Laboratory and Iowa State University
    • Ames Laboratory, US DOE and Iowa State University
    • Ames Laboratory
    • Ames Loboratory, US DOE and Iowa State University
    • Ames Laboratory/Department of Physics and Astronomy
    • Ames Laboratory, US DOE, Iowa State University, Ames, IA 5001, USA

  • R.J. McQueeney

    • Ames Laboratory and Physics Department and Astronomy, Iowa State University, Ames, IA
    • Ames Laboratory and Iowa State University
    • Ames Laboratory, US DOE and Iowa State University
    • Ames Laboratory
    • Ames Laboratory/Department of Physics and Astronomy