engleski

Strong electron-phonon Coupling and Polaron formation in Layered Metal Oxydes

We propose that the main contribution to the electron-phonon coupling in ionic metals like high-T_C superconductors arises from the phonon induced variations of the crystal field. Here we investigate in detail the problem of coupling of the tilting mode in La_2CuO_4, with holes on oxygen sites in CuO_2 planes. It is found that this coupling is quadratic in the phonon field. However, due to the large coupling constant this coupling leads to destabilization of the tilting deformation in orthorhombic La_2CuO_4 when the hole concentration is increased. For small concentrations of holes the tilt deformation is locally suppressed. This can explain the polaron observation in the recent photogeneration experiments.

Layered Metal Oxydes, superconductors

nije evidentirano