Refined spin Hamiltonian for Yb2Ti2O7 and its two competing low field states

Invited

Abstract

We present a neutron scattering study of pyrochlore Yb2Ti2O7 in a [111] magnetic field using high-quality stoichiometric single crystals. High magnetic fields (1.5 T) reveal sharp spin wave modes, which we use to further refine the magnetic Hamiltonian, offering corrections to previous Hamiltonian refinements. Low magnetic fields reveal diffuse features which suggest an unconventional ground state, and we discuss mechanisms explaining how such a spectrum can be caused by proximity to a ferromagnetic-antiferromagnetic phase boundary. We present a model which accounts for the observed spectrum, and resolves several long-standing questions concerning the ground state of Yb2Ti2O7 [1].

[1] A. Scheie, J. Kindervater, G. Sala, G. Ehlers, S. Koopayeh and C. Broholm, in preparation.

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Presenters

  • Allen Scheie

    Johns Hopkins University

Authors

  • Allen Scheie

    Johns Hopkins University

  • Jonas Kindervater

    Johns Hopkins University

  • Gabriele Sala

    Oak Ridge National Lab, Oak Ridge National Laboratory, Neutron Scattering Division, Oak Ridge National Laboratory, Neutron Scattering Division, Oak-Ridge National Laboratory, Neutron Scattering Division, Oak Ridge National Lab

  • Georg Ehlers

    Oak Ridge National Laboratory, Oak Ridge National Lab, SNS, Oak Ridge National Lab, Neutron Scattering Division, Oak-Ridge National Laboratory

  • Seyed Koohpayeh

    Johns Hopkins, Johns Hopkins University, Institute for Quantum Matter, Johns Hopkins University, Henry A. Rowland Department of Physics and Astronomy, Johns Hopkins University

  • Collin Broholm

    Johns Hopkins, Johns Hopkins University, IQM, Johns Hopkins University, Department of Physics and Astronomy, Johns Hopkins University