Emergence of the spin polarized domains in the kagome lattice Heisenberg antiferromagnet Zn-barlowite (Zn0.95Cu0.05)Cu3(OD)6FBr

Kagome lattice Heisenberg antiferromagnets are known to be highly sensitive to perturbations caused by the structural disorder. NMR is a local probe ideally suited for investigating such disorder-induced effects, but in practice, large distributions in the conventional one-dimensional NMR data make it difficult to distinguish the intrinsic behavior expected for pristine kagome quantum spin liquids from disorder-induced effects. Here we report the development of a two-dimensional NMR data acquisition scheme applied to Zn-barlowite (Zn0.95Cu0.05)Cu-3(OD)(6)FBr kagome lattice, and successfully correlate the distribution of the low energy spin excitations with that of the local spin susceptibility. We present evidence for the gradual growth of domains with a local spin polarization induced by 5% Cu2+ defect spins occupying the interlayer non-magnetic Zn2+ sites. These spin-polarized domains account for similar to 60% of the sample volume at 2 K, where gapless excitations induced by interlayer defects dominate the low-energy sector of spin excitations within the kagome planes.

Automated summary

Kagome lattice Heisenberg antiferromagnets are highly sensitive to structural disorder, but distinguishing intrinsic behavior from disorder-induced effects is challenging. In this study, a two-dimensional NMR data acquisition scheme was developed and applied to investigate the Zn-barlowite kagome lattice. The distribution of low energy spin excitations was successfully correlated with the local spin susceptibility, revealing the gradual growth of spin-polarized domains induced by defect spins.