Magnetically ordered and kagome quantum spin liquid states in the Zn-doped claringbullite series

Abstract

Neutron scattering measurements have been performed on deuterated powder samples of claringbullite and Zn-doped claringbullite ${\mathrm{[Zn}}_{x}{\mathrm{Cu}}_{4\ensuremath{-}x}{(\mathrm{OD})}_{6}\mathrm{FCl}$]. At low temperatures, claringbullite ${\mathrm{Cu}}_{4}{(\mathrm{OD})}_{6}\mathrm{FCl}$ forms a distorted pyrochlore lattice with long-range magnetic order and spin-wave-like magnetic excitations. Partial Zn doping leads to the nominal ${\mathrm{ZnCu}}_{3}{(\mathrm{OD})}_{6}\mathrm{FCl}$ compound, a geometrically frustrated spin-1/2 kagome antiferromagnet that shows no transition to magnetic order down to 1.5 K. The magnetic excitations form a gapless continuum, a signature of fractional excitations in a quantum spin liquid.