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 tw o dimensions. Using the hopping basis with over 10(6) states we discus s (for an infinite system) the bandwidth, the leading Fourier coeffici ents in the dispersion, the band masses, and the spin-spin correlation s near the hole. We compare our results with those obtained by other m ethods. The band minimum is found to be at (pi/2, pi/2) for the t-J mo del for 0.1 less than or equal to t/J less than or equal to 10, and fo r 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 la rge t/J, in rough agreement with loop-expansion results but in disagre ement with other results. The strong-coupling bandwidth for t/J greate r 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 dispersi on along the magnetic zone face is flat, giving a large parallel/perpe ndicular band mass ratio.