EXACT DIAGONALIZATION STUDY OF SPIN AND CHARGE DYNAMICS IN THE T-J MODEL

We investigate the dynamical spin-spin and charge-charge correlation f unctions, S(Q,w) and N(and,w), for the two-dimensional t-J model, by u sing the exact diagonalization technique. At high electron density (fo r example, 12 electrons in a 4x4 unit cell), S(Q,w) shows pronounced p eak at low energy of order J and is consistent with 2k(F) low energy e xcitations, whereas N(Q,w) consists of a dense and broad continuum, wh ich is absent from the one-dimensional system. The statistics of eleme ntary charge excitations is also discussed.