BCS-to-BEC evolution details

Melo, Carlos Sa de

doi:10.1063/1.3206105

Cited by 3 publications

(1 citation statement)

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“…( 15) should not significantly depend on the bipolaron size as long as it remains small. On the other hand increasing Ũ in our model finally results in a bipolaron overlap, where the bipolaron condensation should appear in the form of the polaronic Cooper pairs in momentum space [46] with a lower critical temperature, rather than in real space (BEC-BCS crossover [46][47][48][49][50][51]). Hence, we can safely estimate the BEC critical temperature by weighting eq.…”

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confidence: 99%

High-temperature superconductivity from realistic Coulomb and Fröhlich interactions

Alexandrov¹,

Samson²,

Sica³

2012

EPL

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In the last years ample experimental evidence has shown that charge carriers in high-temperature superconductors are strongly correlated but also coupled with lattice vibrations (phonons), signaling that the true origin of high-Tc superconductivity can only be found in a proper combination of Coulomb and electron-phonon interactions. On this basis, we propose and study a model for high-Tc superconductivity, which accounts for realistic Coulomb repulsion, strong electron-phonon (Fröhlich) interaction and residual on-site (HubbardŨ ) correlations without any ad-hoc assumptions on their relative strength and interaction range. In the framework of this model, which exhibits a phase transition to a superconducting state with a critical temperature Tc well in excess of 100K, we emphasize the role ofŨ as the driving parameter for a BEC/BCS crossover. Our model lays a microscopic foundation for the polaron-bipolaron theory of superconductivity. We argue that the high-Tc phenomenon originates in competing Coulomb and Fröhlich interactions beyond the conventional BCS description.

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confidence: 99%