Single-hole properties in the $t$-$J$ and strong-coupling models

TL;DR

This paper presents detailed numerical analysis of single-hole properties in the two-dimensional $t$-$J$ and strong-coupling Hubbard models, revealing the dispersion characteristics, bandwidth, and spin correlations near the hole.

Contribution

It provides comprehensive numerical results for the single-hole dispersion, bandwidth, and correlations in the $t$-$J$ and strong-coupling Hubbard models, comparing with other methods.

Findings

The band minimum is at ($,$) for $t/J$ between 0.1 and 10.

The bandwidth is approximately 2J at large $t/J$, consistent with loop-expansion but not other methods.

The dispersion along the magnetic zone face is flat, indicating a large band mass ratio.

Abstract

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 $0.1 \leq t/J \leq 10$, and for the strong-coupling model for $1 \leq t/J \leq 10$. 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 $t/J\agt6$ 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.