The two-dimensional Hubbard model is studied within the composite operator method (COM) with the electronic self-energy computed in the self-consistent Born approximation (SCBA). The COM describes interacting electrons in terms of the composite elementary excitations appearing in the system owing to the strong correlations; the residual interactions among these excitations are treated within the SCBA. The behavior of the momentum distribution function n (k) is analyzed for various values of filling. In contrast with the ordinary Fermi-liquid behavior found at high doping, non-Fermi-liquid features in n (k) are reported for low doping. These anomalous features are explained by looking at the strong antiferromagnetic correlations developing in the system in proximity of half-filling. © 2006 Elsevier B.V. All rights reserved.
Non-Fermi liquid behavior in the 2D Hubbard model within COM(SCBA)
AVELLA, Adolfo;MANCINI, Ferdinando;PLEKHANOV, Evgeny
2007-01-01
Abstract
The two-dimensional Hubbard model is studied within the composite operator method (COM) with the electronic self-energy computed in the self-consistent Born approximation (SCBA). The COM describes interacting electrons in terms of the composite elementary excitations appearing in the system owing to the strong correlations; the residual interactions among these excitations are treated within the SCBA. The behavior of the momentum distribution function n (k) is analyzed for various values of filling. In contrast with the ordinary Fermi-liquid behavior found at high doping, non-Fermi-liquid features in n (k) are reported for low doping. These anomalous features are explained by looking at the strong antiferromagnetic correlations developing in the system in proximity of half-filling. © 2006 Elsevier B.V. All rights reserved.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
