Thermodynamic properties of extended Hubbard model with strong intraatomic attraction and arbitrary electron density
Abstract
A canonical transformation is used to derive an effective extended Hubbard Hamiltonian with intraatomic repulsion and Ising-type interatomic exchange interaction in an effective external magnetic field from the extended Hubbard model with intraatomic attraction. The absence of magnetic ordering in the original Hamiltonian is transformed into the condition of one quasiparticle per atom. In the strong intraatomic attraction limit, we can further derive from the transformed Hamiltonian an antiferromagnetic anisotropic Heisenberg Hamiltonian in an external field and with a given value of magnetization. A phase diagram of the charge ordered, the singlet superconducting, the mixed, and the nonordered phase is then obtained with the mean field approximation. The collective excitations are examined in the MFA states. For various special cases results reduce to the known results or the exact solutions.
- Publication:
-
Unknown
- Pub Date:
- April 1980
- Bibcode:
- 1980tpeh.rept.....R
- Keywords:
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- Electron Density (Concentration);
- Interatomic Forces;
- Intramolecular Structures;
- Phase Diagrams;
- Thermodynamic Properties;
- Hamiltonian Functions;
- Mathematical Models;
- Transformations (Mathematics);
- Atomic and Molecular Physics