Local properties of the t-J model in a two-pole approximation within COM

Abstract

In this work, we study the t-J model using a two-pole approximation within the composite operator method. We choose a basis of two composite operators -- the constrained electrons and their spin-fluctuation dressing -- and approximate their currents in order to compute the corresponding Green's functions. We exploit the algebraic constraints obeyed by the basis operators to close a set of self-consistent equations that is numerically solved. This allows to determine the physical parameters of the system such as the spin-spin correlation function and the kinetic energy. Our results are compared to those of an exact numerical method on a finite system to asses their reliability. Indeed, a very good agreement is achieved through a far less numerically demanding and a more versatile procedure. We show that by increasing the hole doping, anti-ferromagnetic correlations are replaced by ferromagnetic ones. The behavior on changing temperature and exchange integral is also studied and reported.

References in corpus (7)

• Energy gaps in high-transition temperature cuprate superconductors
• The Hubbard model within the equations of motion approach
• Systematic Mapping of the Hubbard Model to the Generalized t-J Model
• Bosonic sector of the two-dimensional Hubbard model studied within a two-pole approximation
• Effective approach to the Nagaoka regime of the two dimensional t-J model
• Magnetic and nonmagnetic phases in doped AB2 t-J Hubbard chains
• Fifty years of Hubbard and Anderson lattice models: from magnetism to unconventional superconductivity - A brief overview