Averievite: A copper oxide kagome antiferromagnet

Abstract

Averievite, ${\mathrm{Cu}}_{5}{\mathrm{V}}_{2}{\mathrm{O}}_{10}(\mathrm{CsCl})$, is an oxide mineral composed of ${\mathrm{Cu}}^{2+}$ kagome layers sandwiched by ${\mathrm{Cu}}^{2+}\text{\ensuremath{-}}{\mathrm{V}}^{5+}$ honeycomb layers. We have synthesized this oxide and investigated its properties from ab initio calculations along with susceptibility and specific heat measurements. The data indicate a Curie-Weiss temperature of 185 K as well as long-range magnetic order at 24 K due to the significant interlayer coupling from the honeycomb copper ions. This order is suppressed by substituting copper by isoelectronic zinc, suggesting that Zn-substituted averievite is a promising spin liquid candidate. A further proposed substitution that replaces ${\mathrm{V}}^{5+}$ by ${\mathrm{Ti}}^{4+}$ not only dopes the material but is predicted to give rise to a two-dimensional electronic structure featuring Dirac crossings. As such, averievite is an attractive platform for $S=1/2$ kagome physics with the potential for realizing novel electronic states.