Vibronic mechanism of high-Tc superconductivity
Abstract
The dispersion of the in-plane Cu-O bond-stretching longitudinal optical phonon mode in the high-Tc superconducting cuprates shows strong softening with doping near the zone boundary. We suggest that it can be described with a negative electronic dielectric function that results in an overscreening of the intersite Coulomb interaction due to phonon-induced charge transfer and vibronic electron-phonon resonance. We propose that such a strong electron-phonon coupling of specific modes can form a basis for the phonon mechanism of high-temperature superconductivity. With the Eliashberg theory using the experimentally determined electron dispersion and dielectric function, we demonstrate the possibility of superconductivity with the order parameter of the dk2x-k2y symmetry and the transition temperature well in excess of 100 K.
- Publication:
-
Physical Review B
- Pub Date:
- May 2003
- DOI:
- 10.1103/PhysRevB.67.174506
- arXiv:
- arXiv:cond-mat/0212083
- Bibcode:
- 2003PhRvB..67q4506T
- Keywords:
-
- 74.72.-h;
- 74.20.Mn;
- 74.20.Rp;
- Cuprate superconductors;
- Nonconventional mechanisms;
- Pairing symmetries;
- Condensed Matter - Superconductivity
- E-Print:
- 16 pages, 6 figures. Submitted to Phys.Rev.B