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