Research: Field-Angle-Resolved Magnetic Excitations in CeB6

An amazingly rich variety of possible ground states have been observed in different heavy-fermion metals, however one peculiar phase gained extraordinary attention. Interaction between higher-order multipoles leads to the presence of a so-called “hidden order” phase, which is invisible to conventional diffraction techniques. One possible method for characterizing such order is to look at the magnetic excitation spectrum in an applied magnetic field, which bears the imprint of the multipolar interactions and the hidden order parameter in its dispersion relations. Using a specific candidate model, the dispersion for a given field is calculated and then compared to that measured with inelastic neutron scattering. However such an approach suffers from several shortcomings as well as some technical restrictions in the analysis of multipolar magnetic excitations and the possibility to obtain quantitative information about hidden order symmetry and interactions between different multipoles. In order to have a better comparison between the theory and experiment, it is worthwhile to keep the momentum transfer fixed and vary the field strength and field direction. Using this approach we investigated the well-known member of this family of compounds CeB₆ and obtained qualitatively new  information about multipolar excitations. We observe remarkably good agreement between the developed theory of multipolar excitations and measured field-angular dependence for the most intense zone-center excitation.

P. Y. Portnichenko, A. Akbari, S. E. Nikitin, A. S. Cameron, A. V. Dukhnenko, V. B. Filipov, N. Yu. Shitsevalova, P. Čermák, I. Radelytskyi, A. Schneidewind, J. Ollivier, A. Podlesnyak, Z. Huesges, J. Xu, A. Ivanov, Y. Sidis, S. Petit, J.-M. Mignot, P. Thalmeier, D. S. Inosov,
Field-Angle-Resolved Magnetic Excitations as a Probe of Hidden-Order Symmetry in CeB₆,
Phys. Rev. X 10, 021010 (2020)