Electrochemical Control of Magnetism on the Breathing Kagome Network of Li_xScMo₃O₈

Controlling properties within a given functional inorganic material structure type is often accomplished through tuning the electronic occupation, which is in turn dictated by the elemental composition determined at the time of material preparation. We employ electrochemical control of the lithium content, with associated electronic occupancy control, to vary the magnetic properties of a material where a kagome-derived network of Mo₃ triangles carry the spin. In this case, Li is electrochemically inserted into LiScMo₃O₈, a layered compound containing a breathing Mo kagome network. Up to two additional Li can be inserted into LiScMo₃O₈, transforming it into Li₃ScMo₃O₈. Li₂ScMo₃O₈ prepared by electrochemical lithiation is compared to the quantum spin liquid candidate compound Li₂ScMo₃O₈ prepared through high-temperature solid-state methods, which has a slightly different structural stacking sequence but a similar kagome-derived network. Magnetic measurements are supported by first-principles calculations, showing that electrons remain localized on the Mo clusters throughout the doping series. As x is varied in Li_xScMo₃O₈, the measurements and calculations reveal the evolution from a diamagnetic band insulator at x = 1 to a geometrically frustrated magnet at x = 2, back to a diamagnetic insulator at x = 3. These results indicate a likelihood of strong coupling between the degree of Li disorder and charge/magnetic ordering over the Mo₃ clusters.