Exact diagonalization studies of a one-dimensional system at electron density rho=0.4: effect of the Coulomb repulsions and distant transfer
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| Title: | Exact diagonalization studies of a one-dimensional system at electron density rho=0.4: effect of the Coulomb repulsions and distant transfer |
| Authors: | Ouchni, Fatiha |
| Thesis advisor: | Apl. Prof. Dr. Juergen Schnack |
| Thesis referee: | Apl. Prof. Dr. Klaus Betzler |
| Abstract: | An extended Hubbard model with large short and long-ranged Coulomb repulsions and distant transfer is numerically investigated by use of the Lanczos exact diagonalization (ED) method to study the charge order and unconditional dimerization of a chain at density rho (ρ)= 0.4. From the analysis of the spin and charge correlation functions, a picture consistent with the formation of a dimer insulating state, which is of Wigner lattice-type (WL) charge order (CO), is obtained. The next-nearest neighbour (NNN) hopping t2 enhances the intradimer correlations and weakens the interdimer correlations. Implications for the CuO2 chains in Sr14Cu24O41 are discussed.We have also introduced a Heisenberg model which parametrically depends on hole positions. If the electrostatic hole-hole repulsion is included such a model allows to evaluate all energy eigenvalues and eigenstates (for small system size) and thus enables us to evaluate thermodynamic properties as function of temperature,magnetic field, and doping. Assuming certain exchange constants we can investigate the influence of the electrostatic hole-hole repulsion on ground state properties as well as on thermal averages like the magnetization which include contributions of low-lying spin-hole configurations. |
| URL: | https://osnadocs.ub.uni-osnabrueck.de/handle/urn:nbn:de:gbv:700-2006092719 |
| Subject Keywords: | Exact diagonalization; extended hubbard model; Coulomb repulsion; distant transfer; charge order; dimerization; Heisenberg model; magnetization |
| Issue Date: | 25-Sep-2006 |
| Submission date: | 25-Sep-2006 |
| Type of publication: | Dissertation oder Habilitation [doctoralThesis] |
| Appears in Collections: | FB06 - E-Dissertationen |
Files in This Item:
| File | Description | Size | Format | |
|---|---|---|---|---|
| E-Diss598_thesis.tar.gz | 1,24 MB | GZIP | E-Diss598_thesis.tar.gz View/Open | |
| E-Diss598_thesis.pdf | Präsentationsformat | 789,47 kB | Adobe PDF | E-Diss598_thesis.pdf  View/Open |
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