Dynamics of strongcoupling models for cuprate superconductors: Exact results on finite lattices
Abstract
We discuss recent applications of exact numerical continued fraction expansion (CFE) techniques to calculate dynamical correlation functions of various strongcoupling models related to the hightemperature cuprate superconductors. For the twodimensional squarelattice spin1/2 Heisenberg antiferromagnet, we present exact results for the zerotemperature dynamical structure factor on finitesized lattices and compare them to approximate results from a Schwinger boson meanfield theory, recently proposed by Arovas and Auerbach. We find that the meanfield theory represents a very good approximation to the exact spin excitation spectra and to the static spin correlations. We then investigate the dynamical spinspin structure factor and the singleparticle spectral function for finite model clusters with dopant induced holetype charge carriers, in the strongcoupling limit of both the singleband Hubbard model (tJmodel) and the threeband Hubbard model (KondoHeisenberg model). Our results are consistent with the physical picture recently proposed by Zhang and Rice which implies an approximate mapping of the lowenergy states in the threeband model onto an effective singleband theory.
 Publication:

Presented at the Los Alamos Workshop on Quantum Simulations of Condensed Matter Phenomena
 Pub Date:
 1989
 Bibcode:
 1989qscm.work....8S
 Keywords:

 Antiferromagnetism;
 Bosons;
 Copper Oxides;
 Crystal Lattices;
 Field Theory (Physics);
 High Temperature Superconductors;
 Lattice Parameters;
 Atomic Excitations;
 Correlation;
 Heisenberg Theory;
 Kondo Effect;
 Mathematical Models;
 Spectral Theory;
 Spin;
 SolidState Physics