The two-dimensional antiferromagnetic Heisenberg model and $t - J$ model are studied on the square lattice aimed to understand certain normal state properties of the high-temperature copper-oxide superconductors. Fundamental physical issues such as the role of quantum spin fluctuations, and hole dynamics are addressed. We constructed a variational wave function for the Heisenberg model, which includes spin-spin correlations and possesses antiferromagnetic long range order. Long and short wave length spin excitations are calculated using this wave function and compared with neutron scattering and Raman scattering experiments. Loop-expansions up to two-loop level are applied to study the spectral function of a single hole described by the $t - J$ model. Our numerical solutions extrapolated to the thermodynamical limit show that the hole spectral function consists of a sharp lowest-energy quasihole peak and a series of well defined peaks above it, which correspond to the "string" excitations. The single hole spectral weight of the t-J model is also calculated using the Green's function Monte Carlo method to further clarify the controversial question of whether or not the Fermi liquid theory breaks down in this model due to a vanishing spectral weight. / Source: Dissertation Abstracts International, Volume: 54-03, Section: B, page: 1473. / Major Professor: Efstratios Manousakis. / Thesis (Ph.D.)--The Florida State University, 1993.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_76897 |
| Contributors | Liu, Zhiping., Florida State University |
| Source Sets | Florida State University |
| Language | English |
| Detected Language | English |
| Type | Text |
| Format | 145 p. |
| Rights | On campus use only. |
| Relation | Dissertation Abstracts International |
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