Tight-binding electronic structure of high Tc superconductors

New superconducting oxides have important crystallographic similarities. They are bulk perovskites or structure derived compounds, with an alternating nature: the oxygen atoms nearest-neighbours are metallic atoms and vice-versa. We show that this structural property has important consequences on the electronic structure. We first present a general formalism allowing us to describe in a simple way the electronic structure as soon as one has an alternating lattice. In a second part, we illustrate this method for different oxides related with the high Tc superconductors. Lastly, we show the results we obtain with the alternating lattice method in the two-band model of the CuO2 plane which is characteristic of the copper-based new superconductors