Dynamics of holes and universality class of the antiferromagnetic transition in the two-dimensional Hubbard model

The dynamics of a single hole (or electron) in the two-dimensional Hubbard model is investigated. The antiferromagnetic background is described by a N eel state, and the hopping of the carrier is analyzed within a configuratio n interaction approach. Results are in agreement with other methods and wit h experimental data when available. All data are compatible with the openin g of a mean field gap in a Fermi liquid of spin polarons, the so called Sla ter type of transition. In particular, this hypothesis explains the unusual dispersion relation of the quasiparticle bands near the transition. Recent photoemission data for Ca2CUO2Cl2 are analyzed within this context. (C) 20 00 Elsevier Science Ltd. All rights reserved.