Kapellasite: a kagome quantum spin liquid

TL;DR

This study investigates kapellasite, a kagome antiferromagnet, revealing it as a gapless spin liquid with persistent dynamic correlations, characterized through various experimental techniques and theoretical modeling.

Contribution

It provides detailed experimental characterization and theoretical analysis of kapellasite as a gapless quantum spin liquid with unique non-coplanar correlations.

Findings

Kapellasite is a gapless spin liquid with persistent short-range correlations.

Experimental data fit a specific Hamiltonian with frustrated interactions.

Theoretical calculations support the experimental observations.

Abstract

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.