  The local quasiparticle density of states around a unitary impurity with a
Kondo-like magnetic moment induced at its nearest neighbors in a d-wave
superconductor is studied within the slave-boson mean-field approach. The
Hamiltonian is exactly diagonalized and the results are obtained
self-consistently. We show that the interference between the strong impurity
potential scattering and the Kondo effect leads to novel quasiparticle spectra
around the impurity, which are strikingly different from the case of a single
unitary or magnetic impurity. The recent STM image of the local differential
tunneling conductance around a Zn impurity in a high-T_c cuprate can be
essentially explained if the blocking effect of BiO surface layer between the
tip and probed CuO_2 plane [Zhu et al., Phys. Rev. B 62, 6207 (2000)] is taken
into account.
