title: Strong antiferromagnetic correlation effects on the momentum distribution function of the Hubbard model.
abstract: Strong antiferromagnetic correlations can radically change the behavior of an otherwise paramagnetic system, inducing anomalous effects in the single particle properties and driving the behavior of spin-spin response functions. In order to investigate such physics, we have studied the momentum distribution function of the two-dimensional Hubbard model at low doping, low temperatures and high values of the on-site Coulomb repulsion. The interpretation of the results has greatly benefited from the parallel analysis of the filling, temperature and interaction dependences of the spin-spin correlation function, the antiferromagnetic correlation length and the pole of the spin-spin propagator. On reducing doping or temperature and on increasing the interaction strength, the correlations become stronger and stronger and the Fermi surface develops hole and electron pockets and shows a dual nature (small-large).
authors.affiliation: Dipartimento di Fisica 'E R Caianiello'-Unità CNISM di Salerno, Università degli Studi di Salerno, I-84081 Baronissi (SA), Italy. Laboratorio Regionale SuperMat, CNR-INFM, I-84081 Baronissi (SA), Italy.
authors.forename: Adolfo
authors.initials: A
authors.lastname: Avella
authors.forename: Ferdinando
authors.initials: F
authors.lastname: Mancini