Averievite: a copper oxide kagome antiferromagnet

Abstract

Averievite, Cu${}_5$V${}_2$O${}_{10}$(CsCl), is an oxide mineral composed of Cu${}^{2+}$ kagome layers sandwiched by Cu${}^{2+}$-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 these coppers by isoelectronic zinc, suggesting that Zn-substituted averievite is a promising spin liquid candidate. A further proposed substitution that replaces V${}^{5+}$ by 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.