A hierarchy of ``meson" bound state excitations in the 1D ferromagnetic Ising chain CoNb$_2$O$_6$

ORAL

Abstract

The quantum magnet CoNb$_2$O$_6$ was recently demonstrated to be an excellent realization of the one-dimensional ferromagnetic Ising spin chain. Low energy spin-flip excitations in the chains were recently observed via inelastic neutron scattering.\footnote{R. Coldea, \textit{et al}, Science \textbf{327}, 177 (2010)} The energy spectrum of these excitations was shown to have a interesting energy scaling governed by symmetries of the E8 exceptional Lie group. Here, time-domain terahertz spectroscopy (TDTS) is used to investigate these optically active spin flip excitations in CoNb$_2$O$_6$. A series of nine spin flip bound states is observed, whose energies can be modeled exceedingly well by the Airy function solutions to a 1D Schr{\"o}dinger equation. Additionally, a novel bound state of excitations on neighboring chains is observed just below the onset of a two particle continuum.

*Work supported by The Institute of Quantum Matter under DOE grant DE-FG02-08ER46544 and by the Gordon and Betty Moore Foundation through Grant GBMF2628.

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Authors

  • Christopher Morris

    • The Institute for Quantum Matter, Department of Physics \& Astronomy, The Johns Hopkins University, Baltimore, MD 21218

  • Seyed Koopayeh

    • The Institute for Quantum Matter, Department of Physics \& Astronomy, The Johns Hopkins University, Baltimore, MD 21218

  • Anirban Ghosh

    • The Institute for Quantum Matter, Department of Physics \& Astronomy, The Johns Hopkins University, Baltimore, MD 21218

  • Oleg Tchernyshyov

    • The Institute for Quantum Matter, Department of Physics \& Astronomy, The Johns Hopkins University, Baltimore, MD 21218

  • Tyrel M. McQueen

    • The Institute for Quantum Matter, Department of Physics \& Astronomy, The Johns Hopkins University, Baltimore, MD 21218

  • N. Peter Armitage

    • The Institute for Quantum Matter, Department of Physics \& Astronomy, The Johns Hopkins University, Baltimore, MD 21218

  • Rolando Vald\'es Aguilar

    • Center for Integrated Nanotechnologies, Los Alamos National Laboratory. MS K771. Los Alamos, NM 87545

  • Jason Krizan

    • Department of Chemistry, Princeton University, Princeton, NJ 08544

  • Robert J. Cava

    • Department of Chemistry, Princeton University, Princeton, NJ 08544