Novel interplay of Fermi-surface behavior and magnetism in a low-dimensional organic conductor

We have used the magneto-oscillatory behavior of the quasi-two-dimensional orbits in the charge-transfer organic salt (BEDT-TTF${)}_2$KHg(SCN${)}_4$ to probe its underlying magnetic ground states, which arise from the coexisting quasi-one-dimensional nature of the material. The complex nature of the oscillations results from the field dependence of these states. Our results allow comparison between several competing models which have attempted to describe the unusual properties of this material.