Electronic structure of the high Tc superconductor Ba2YCu3O6.9

Abstract The electronic structure of Ba 2 YCu 3 O 6.9 has been calculated using the linear augmented-plane-wave method. The results show strongly 2-dimensional and 1-dimensional features in the energy bands. These gives rise to competing charge density wave instabilities. We argue that the proximity of these instabilities and the large electron-phonon matrix elements of the Fermi-level electrons make important contributions to the high T c of this material.