Abstract
Numerical calculations illustrate the effect of the sign of the next-nearest-neighbor hopping term on the two-hole properties of the model. Working mainly on two-leg ladders, in the regime, it is shown that introducing in the model is equivalent to effectively renormalizing J, namely negative (positive) is equivalent to an effective model with smaller (bigger) J. This effect is present even at the level of a plaquette toy model, and was observed also in calculations on small square clusters. Analyzing the transition probabilities of a hole pair in the plaquette toy model, it is argued that the coherent propagation of such hole pair is enhanced by a constructive interference between both t and for This interference is destructive for
- Received 16 July 2001
DOI:https://doi.org/10.1103/PhysRevB.64.180513
©2001 American Physical Society