In these notes we review some of the basic features of the 2D Hubbard model, thought of as the appropriate model for the description of the Cu - O planes in the cuprate superconductors. We discuss briefly the weak-coupling regime of the model and, in the opposite limit, the mapping of the one band Hubbard model onto an AFM Heisenberg model at half filling and onto the t - J model below half filling. We discuss next Emery's three band model and its mapping onto the so-called "spin-fermion" model. Its continuum limit is discussed by making use of an adiabatic followed by a gradient expansion. We review briefly how the model maps onto a nonlinear sigma model and some of the features of the latter.
An introduction to the Hubbard model
PIERI, Pierbiagio
1997-01-01
Abstract
In these notes we review some of the basic features of the 2D Hubbard model, thought of as the appropriate model for the description of the Cu - O planes in the cuprate superconductors. We discuss briefly the weak-coupling regime of the model and, in the opposite limit, the mapping of the one band Hubbard model onto an AFM Heisenberg model at half filling and onto the t - J model below half filling. We discuss next Emery's three band model and its mapping onto the so-called "spin-fermion" model. Its continuum limit is discussed by making use of an adiabatic followed by a gradient expansion. We review briefly how the model maps onto a nonlinear sigma model and some of the features of the latter.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
