Effective single-band Hamiltonian for electron-phonon coupling in cuprate superconductors
- Pennsylvania State Univ., University Park, PA (United States)
The authors derive an effective single-band Hubbard type Hamiltonian for CuO{sub 2} planes. The Hamiltonian includes both electron-electron repulsion and electron-phonon coupling to oxygen vibrational modes. They start with first-principles density functional theory parameters and then map onto a single-band model. Unlike previous mappings to a single-band Hamiltonian, this work explicitly preserves the Fermi surface shape and matrix elements of the many-band Hamiltonian. The authors consider both in-plane oxygen breathing modes as well as out-of-plane tilting modes. The latter modes have a quadratic electron-phonon coupling, and are also highly anharmonic in La{sub 2}CuO{sub 4} based superconductors. The coupling to breathing modes is too small to account for high {Tc}, while the coupling to quadratic modes is much stronger even though they would be neglected in a standard Migdal-Eliashberg approach to superconductivity.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 106846
- Journal Information:
- Journal of Superconductivity, Vol. 7, Issue 6; Other Information: PBD: Dec 1994
- Country of Publication:
- United States
- Language:
- English
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