Nonmagnetic impurities in the spin-1/2 kagome antiferromagnet

Motivated by recent experiments on ZnCu3(OH)6Cl2, we study the inhomogeneous Knight shifts (local susceptibilities) of a spin-1/2 kagome antiferromagnet in the presence of nonmagnetic impurities. Using high temperature series expansion, we calculate the local susceptibility and its histogram down to about T=0.4J. At low temperatures, we explore a Dirac spin liquid proposal and calculate the local susceptibility in the mean field and beyond mean field using Gutzwiller projection, finding the overall picture to be consistent with the NMR experiments.