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

TL;DR

This study investigates the magnetic properties of Zn-doped claringbullite, revealing a transition from long-range magnetic order to a quantum spin liquid state with fractional excitations in the kagome lattice.

Contribution

It provides experimental evidence of a quantum spin liquid state in Zn-doped claringbullite, highlighting the role of doping in inducing geometrical frustration and fractional excitations.

Findings

Pure claringbullite exhibits long-range magnetic order.

Zn doping suppresses magnetic order, leading to a quantum spin liquid.

The doped compound shows a gapless continuum of magnetic excitations.

Abstract

Neutron scattering measurements have been performed on deuterated powder samples of claringbullite and Zn-doped claringbullite (Zn$_x$Cu$_{4-x}$(OD)$_{6}$FCl). At low temperatures, claringbullite Cu$_4$(OD)$_{6}$FCl forms a distorted pyrochlore lattice with long-range magnetic order and spin-wave-like magnetic excitations. Partial Zn doping leads to the nominal ZnCu$_3$(OD)$_{6}$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.