Coexisting spinons and magnons in the frustrated zigzag spin- 12 chain compound β−TeVO4

We investigate magnetic excitations in the frustrated zigzag spin-1/2 chain compound $\ensuremath{\beta}\text{\ensuremath{-}}{\mathrm{TeVO}}₄$ by inelastic neutron scattering. In the magnetically ordered ground state, the excitation spectrum exhibits coexisting magnon dispersion, characteristic of long-range magnetic order, and a spinon-like continuum that prevails above $\ensuremath{\sim}2\phantom{\rule{0.16em}{0ex}}\mathrm{meV}$, indicating the dominance of intrachain interactions. Combining linear-spin-wave-theory and precalculated spinon-continuum results, we reproduce the experimental spectrum. Our analysis offers a minimal exchange-network model, which determines dominant intrachain interactions, their anisotropies, and weak interchain interactions. The obtained parameters explain the magnetic ordering vector and spin excitations in the magnetic ground state.