Kapellasite: a kagome quantum spin liquid
  Magnetic susceptibility, NMR, muSR, and inelastic neutron scattering measurements show that kapellasite, Cu3Zn(OH)6Cl2, a geometrically frustrated spin-1/2 kagome antiferromagnet polymorphous with the herbertsmithite mineral, is a gapless spin liquid with frustrated interactions showing unusual dynamic short-range correlations of non-coplanar cuboc2 type which persist down to 20 mK. The Hamiltonian is determined from a fit of a high-temperature series expansion to thermodynamical data. The experimental data are compared to theoretical calculations using the Schwinger-boson approach. 
B. F{\aa}k, E. Kermarrec, L. Messio, B. Bernu, C. Lhuillier, F. Bert,   P. Mendels, B. Koteswararao, F. Bouquet, J. Ollivier...
cond-mat.str-el