Dynamics of strong-coupling 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 strong-coupling models related to the high-temperature cuprate superconductors. For the two-dimensional square-lattice spin-1/2 Heisenberg antiferromagnet, we present exact results for the zero-temperature dynamical structure factor on finite-sized lattices and compare them to approximate results from a Schwinger boson mean-field theory, recently proposed by Arovas and Auerbach. We find that the mean-field theory represents a very good approximation to the exact spin excitation spectra and to the static spin correlations. We then investigate the dynamical spin-spin structure factor and the single-particle spectral function for finite model clusters with dopant induced hole-type charge carriers, in the strong-coupling limit of both the single-band Hubbard model (t-J-model) and the three-band Hubbard model (Kondo-Heisenberg model). Our results are consistent with the physical picture recently proposed by Zhang and Rice which implies an approximate mapping of the low-energy states in the three-band model onto an effective single-band theory.
- Publication:
-
Presented at the Los Alamos Workshop on Quantum Simulations of Condensed Matter Phenomena
- Pub Date:
- 1989
- Bibcode:
- 1989qscm.work....8S
- Keywords:
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- 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;
- Solid-State Physics