Local Spin Susceptibility of the S=1/2 Kagome Lattice in ZnCu3(OD)6Cl2

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We report single-crystal 2-D NMR investigation of the nearly ideal spin S=1/2 kagome lattice ZnCu3(OD)6Cl2.

• We successfully identify 2-D NMR signals originating from the nearest-neighbors of Cu2+ defects occupying Zn sites.
• From the 2-D Knight shift measurements, we demonstrate that weakly interacting Cu2+ spins at these defects cause the large Curie-Weiss enhancement toward T=0 commonly observed in the bulk susceptibility data.
• We estimate the intrinsic spin susceptibility of the kagome planes by subtracting defect contributions, and explore several scenarios.