Magnetic Impurity in the two-dimensional Heisenberg Antiferromagnet
  We analyze the ground state properties of the two-dimensional quantum antiferromagnet with a S=1/2 Kondo impurity. Perturbation theory around the strong Kondo coupling limit is developed and the results compared with studies, based on exact diagonalization of small clusters. We find that at intermediate coupling the impurity is partially screened and the magnetization locally suppressed. A local singlet between the impurity and the host spin is formed asymptotically. 
V.N. Kotov, J. Oitmaa, and O. Sushkov (UNSW)