RAMAN-SPECTRUM IN THE T-J MODEL

We have studied, using exact diagonalization techniques, the Raman spectrum in the t-J model in the zero- and one-hole subspace. In both sectors we obtain a very good agreement with experimental measurements in the B1g geometry. In the doped case the spectrum becomes broader, it is shifted to lower frequencies, and the peak at 2.97J, identified as a two-magnon process, disappears. We found that the low-energy excitations are string states and two-magnon processes in the neighborhood of the hole. © 1990 The American Physical Society.