Interlayer tuning of electronic and magnetic properties in honeycomb ordered Ag3LiRu2O6

Abstract

We report a switching of electronic, magnetic and lattice properties in honeycomb ruthenates by interlayer cation exchange. The new material Ag₃LiRu₂O₆ was made by ion-exchange of the ordered Li/Ru honeycomb material Li₂RuO₃ in an AgNO₃ melt at 200 °C. Neutron powder diffraction and electron microscopy show that the Li/Ru order is preserved in the honeycomb layers, however, significant stacking disorder is found between layers. In contrast to Li₂RuO₃, which is insulating, dimerised and diamagnetic, Ag₃LiRu₂O₆ has low electrical resistivity (0.01 ohm cm⁻¹) and a large magnetic susceptibility at room temperature. This is attributed to the electronic influence of the highly polarisable interlayer Ag⁺ cation. The combination of two dimensionality, good conductivity and stacking disorder means this family of materials have potential for thermoelectric applications.