| Issue |
Ann. Phys. Fr.
Volume 13, Number 5, 1988
|
|
|---|---|---|
| Page(s) | 431 - 435 | |
| DOI | https://doi.org/10.1051/anphys:01988001305043100 | |
| Published online | 01 June 2004 | |
Competition between charge ordering and superconductivity in La 2-xMxCuO4
Institute for Low Temperature and Structure Research, Polish Academy of Sciences, 53-529 Wroclaw, ul. Próchnika 95, Poland
The interplay between charge density waves (CDW) and Bose condensation of local hole pairs in systems with strong electron-phonon interaction [1] is analysed on the basis of the negative U Hubbard Hamiltonian and local pair superconductor model. The Landau free energy functional with two competing order parameters is derived from microscopic considerations and the temperature-concentration (T - x) phase diagrams relevant for La2-xMxCuO4 (M = Ba, Ca, Sr) compounds are calculated.
Résumé
On analyse les relations entre les ondes de densité de charge et la condensation de Bose de paires locales de trous dans des systèmes à forte interaction électron-phonon [1] ; on utilise pour cela un hamiltonien de Hubbard à U négatif et un modèle de supraconductibilité à paires locales. A partir de considérations microscopiques on obtient l'énergie libre sous la forme d'une fonctionnelle de Landau avec deux paramètres d'ordre en compétition ; on en déduit, dans 1e plan température-concentration (T - x), les diagrammes de phase correspondant aux composés La2-xMxCuO4 où M = Ba, Ca, Sr.
PACS: 7420 – Theory of superconductivity / 7470V – Perovskite phase superconductors / 7145L – Charge density wave systems / 6320K – Phonon electron interactions / 7138 – Polarons and electron phonon interactions
Key words: barium compounds / calcium compounds / charge density waves / electron phonon interactions / free energy / high temperature superconductors / Hubbard model / lanthanum compounds / strontium compounds / high temperature superconductor / charge ordering / superconductivity / charge density waves / Bose condensation / local hole pairs / strong electron phonon interaction / negative U Hubbard Hamiltonian / local pair superconductor model / Landau free energy functional / order parameters / phase diagrams / La sub 2 x Ba sub x CuO sub 4 / La sub 2 x Sr sub x CuO sub 4 / La sub 2 x Ca sub x CuO sub 4
© EDP Sciences, 1988