SINGLE-HOLE PROPERTIES IN THE T-J AND STRONG-COUPLING MODELS

We report numerical results for the single-hole properties in the t-J model and the strong-coupling approximation to the Hubbard model in two dimensions. Using the hopping basis with over 10(6) states we discuss (for an infinite system) the bandwidth, the leading Fourier coefficients in the dispersion, the band masses, and the spin-spin correlations near the hole. We compare our results with those obtained by other methods. The band minimum is found to be at (pi/2, pi/2) for the t-J model for 0.1 less than or equal to t/J less than or equal to 10, and for the strong-coupling model for 1 less than or equal to t/J less than or equal to 10. The bandwidth in both models is approximately 2J at large t/J, in rough agreement with loop-expansion results but in disagreement with other results. The strong-coupling bandwidth for t/J greater than or similar to, 6 can be obtained from the t-J model by treating the three-site terms in first-order perturbation theory. The dispersion along the magnetic zone face is flat, giving a large parallel/perpendicular band mass ratio.