Anomalously strong small-q electron-phonon coupling in cuprates due to dielectricity |
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Authors: | M. Weger |
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Affiliation: | (1) Racah Institute of Physics, Hebrew University, Jerusalem, Israel |
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Abstract: | We consider the role of the enormous ionic dielectric constant ε0≈ 30–50 in the cuprates. The ionically-screened Thomas-Fermi screening parameter ~qTF = [4θe2N(EF)/εin0 1/2 is extremely small, namely 0.2-0.3 A-1. The electron-phonon coupling constant I(q,w) is found to be anomalously large forq ≈ ~qTF and smallco, accounting for the CDW observed in overdoped BSCCO with wavevector 0.24 A-1. Using the Eliashberg theory we derive from this I(q,w) a maximumT c of about 200 K. The small electron-phonon scattering angle △θ = ~q F ≈ 0.3 rad acounts for the observedd-wave pairing, as originating from a phonon-mediated mechananism. |
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Keywords: | Electron-phonon coupling cuprates dielectricity |
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