The role of thermal disorder on the electronic structure in high-T-c compounds

The electronic structures of YBa2Cu3O7, HgBa2CuO4 and Bi2Sr2CaCu2O8 are cal culated for lattice distortions corresponding to different temperatures. Su ch distortions, including the zero-point motion, are found to be responsibl e for band broadenings and modifications of the Fermi surface. The density- of-states (DOS) near the Fermi energy, E-F, shows important changes for som e modes involving atomic z-displacements as well as for in-plane distortion s within the CuO2 layer, in addition our calculations show that the electro n-phonon coupling (lambda) will be much enhanced for such modes. The conseq uences of this result on superconducting and normal state properties are di scussed. (C) 2000 Elsevier Science B.V. All rights reserved.