HOLE POCKETS IN THE T-J MODEL

We present an exact diagonalization study of the electron momentum distribution n(k) for small clusters of the model t-J model for different hole concentrations and t/J. To obtain reliable information about the Fermi surface, we focus on the regime t<J, where the backflow effect is weak, and we suppress the formation of a bound state by introducing a density repulsion between holes. We find clear signatures of a Fermi surface which takes the form of small hole pockets. Comparison of the scaling of n(k) and that of the quasiparticle weight with t/J suggests that these pockets persist also for t>J. © 1995 The American Physical Society.