SPIN AND CHARGE DYNAMICS OF THE T-J MODEL

We investigate the dynamical spin and charge correlation functions, S(Q, ω) and N(Q, ω), for the two-dimensional (2D) t-J model by using the exact diagonalization technique. Both quantities are compared with the 1D t-J model. At high electron density (n>0.7), a remarkable feature emerges: S(Q, ω) shows a pronounced peak at low energy of order J which is consistent with 2kF low-energy excitations, whereas low-energy 2kF-backscattering processes are strongly suppressed in the charge-density response. N(Q, ω) consists of a dense and broad continuum, qualitatively different from the 1D charge response, implying strong interactions between charge and spin degrees of freedom. © 1995 The American Physical Society.