Neutron Scattering Study of Kitaev Spin-Liquid Candidate H₃LiIr₂O₆

A central theme of condensed matter physics in recent years has been the realization of materials that exhibit a quantum spin-liquid state beyond one dimension. The exactly solvable Kitaev model of a quantum spin liquid consists of a 2D honeycomb lattice of J_eff = ½ magnetic ions with bond dependant interactions. NMR and bulk sample characterization has suggested that H₃LiIr₂O₆ could be a spin-liquid [1]. The structure consists of a honeycomb lattice of Ir⁴⁺ ions with strong spin-orbit coupling to support the bond dependent exchange interactions required in the Kitaev model. While previous litium irdates have all been found to magnetically order at low temperature, specific heat and magnetization measurements show no order in this material down to low temperature. Using inelastic neutron scattering on SEQUOIA at ORNL, we probed the material magnetic excitations in D₃⁷Li¹⁹³Ir₂O₆. We describe features in neutron scattering which are consistent with those of a KSL. Through a first moment analysis of the scattering data we determine the range of interactions and an estimate for the ground state energy.
[1]K. Kitagawa, T. Takayama, Y. Matsumotot, A. Kato, R. Takano, Y. Kishimoto, S. Bette, R. Dinnebier, G. Jackeli, H. Takagi, Nature 554, 25482 (2018)