Continuum of magnetic excitations in the Kitaev honeycomb iridate D₃LiIr₂O₆

Inelastic neutron scattering (INS) measurements of powder D₃(⁷Li)(¹⁹³Ir)₂O₆ reveal low energy magnetic excitations with a scattering cross section that is broad in $|Q|$ and consistent with a Kitaev spin-liquid (KSL) state. The magnetic nature of the excitation spectrum is demonstrated by longitudinally polarized neutron studies. The total magnetic moment of 1.7(2)μB/Ir inferred from the total magnetic scattering cross section is consistent with the effective moment inferred from magnetic susceptibility data and expectations for the Jeff=1/2 single ion state. The rise in the dynamic correlation function S(Q,ω) for ω<5~meV can be described by a nearest-neighbor Kitaev model with interaction strength K≈-13(5)~meV. Exchange disorder associated with the mixed D-Li site could play an important role in stabilizing the low T quantum fluctuating state.