Terahertz excitation of magnon modes in CaFe$_2$O$_4$

ORAL

Abstract

We report on the q=0 magnetic excitations in the orthorhombic antiferromagnet CaFe$_2$O$_4$, using time-domain terahertz spectroscopy. Multiple excitations were observed, with different selection rules. The temperature dependence of these excitations reveals their magnetic origin. Interestingly, we find that the gap excitation is split into two of slightly different energies for two different THz polarizations. This suggests that there are two easy-plane single ion anisotropy energies that split the gap at the magnetic zone center. We can explain the different excitation energies and their selection rules using classical spin wave theory.

*The work at Ohio State University was supported by the Center of Emergent Materials, an NSF MRSEC, under grant DMR-1420451.
The work at Rutgers University was supported by the DOE under Grant No. DOE: DE-FG02-07ER46382.

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Presenters

  • Thuc Mai

    • Department of Physics, Ohio State Univ - Columbus
    • Physics, Ohio State University - Columbus
    • Center for Emergent Materials. Department of Physics, The Ohio State University
    • Department of Physics , The Ohio State University

Authors

  • Thuc Mai

    • Department of Physics, Ohio State Univ - Columbus
    • Physics, Ohio State University - Columbus
    • Center for Emergent Materials. Department of Physics, The Ohio State University
    • Department of Physics , The Ohio State University

  • Lunyong Zhang

    • Max Planck POSTETH, Pohang University of Science and Technology
    • Korea Research Initiative
    • Laboratory for Pohang Emergent Materials and Max Plank POSTECH Center for Complex Phase Materials, Pohang University of Science and Technology

  • Sang-Wook Cheong

    • Rutgers University
    • Department of Physics and Astronomy, Rutgers University
    • Department of Physics and Astronomy, Rutgers, The State University of New Jersey
    • Physics, Rutgers University
    • Physics and Astronomy, Rutgers University
    • Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University
    • Physics and Astronomy, Rutgers Univ.
    • Rutgers Univ
    • Physics, Rutgers Univesity
    • Department of Physics, Rutgers University
    • Physics and Astronomy, Rutgers Center for Emergent Materials
    • Department of Physics & Astronomy , Rutgers University

  • Rolando Valdes Aguilar

    • Department of Physics, Ohio State Univ - Columbus
    • Center for Emergent Materials. Department of Physics, The Ohio State University
    • Physics, Ohio State University - Columbus
    • Ohio State Univ - Columbus
    • Department of Physics , The Ohio State University