Magnon-spinon dichotomy in the Kitaev hyperhoneycomb β − Li 2 IrO 3

The spin-orbit entangled nature of the magnetic moments in Kitaev materials is expected to give rise to a quantum spin liquid (QSL) state with fractional excitations. Using resonant inelastic x-ray scattering under a magnetic field, here the authors map the excitation spectra of $\ensuremath{\beta}$-Li${}_{2}$IrO${}_{3}$. They observe a dichotomy between a magnon-like response at low energies, originating from intertwined field-induced ground states, and a multi-spinon-like continuum at higher energies, originating from pairwise excitations of long-lived Majorana fermions of the proximate QSL.