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Superlight bipolarons and criterion of BCS-BEC crossover in cuprates
preprint
posted on 2006-04-03, 15:51 authored by A.S. AlexandrovMost of the proposed models of high-temperature superconductivity (HTSC) are based on the short-range electron-electron correlations or/and on a short-range electron-phonon interaction. However, in the cuprates the screening is poor due to a low carrier density, layered crystal structure, and high ionicity of the lattice. We develop further the bipolaron model of HTSC, which explicitly takes into account the long-range origin of all interactions. The long-range electron-phonon (Froehlich) interaction binds carriers into real space pairs (small bipolarons) with surprisingly low mass but sufficient binding energy, while the long-range Coulomb repulsion keeps them from forming larger clusters. The model has explained many key features of cuprates. Here it is shown that real-space pairing takes place in many cuprates at variance with some (incorrect) criteria of the BCS-BEC crossover.
History
School
- Science
Department
- Physics
Pages
1124074 bytesPublication date
2003Notes
This is a pre-print. The definitive version: ALEXANDROV, A.S., 2003. Superlight bipolarons and criterion of BCS-BEC crossover in cuprates. International Journal of Modern Physics, B17(18-20), pp. 3315-3318.Language
- en