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Superconductivity from electron-phonon interactions in the absence of electron-hole symmetry
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F. Marsiglio, J.E. Hirsch,
Physica B 199-200, 338 (1994)
We consider an electron-phonon Hamiltonian where the electron-phonon interaction occurs through a modification of both the electron on-site energy and the inter-site hopping amplitude, i.e. a combination of Holstein and Su-Schrieffer-Heeger (SSH)-like models. It is suggested that this model may apply to certain vibrational degrees of freedom in high Tc oxides. This Hamiltonian is electron-hole asymmetric and reduces in the infinite-frequency limit to a model for hole superconductivity recently discussed. We solve the Eliasberg equations for the model and examine the effect of electron-hole symmetry breaking on Tc in the presence of retardation.

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