STRUCTURAL, DYNAMICAL, AND ELECTRONIC-PROPERTIES OF CACUO2

The scalar relativistic version of an accurate first-principles full-potential self-consistent linearized muffin-tin-orbital (LMTO) method has been employed for describing the physical properties of the parent system of the high-T(c) oxide superconductors, i.e., CaCuO2. The presently employed modified version of the LMTO method is quite fast and extends the usual LMTO-ASA (atomic-sphere approximation) method in the sense that it permits a completely general shape of the potential and the charge density and is also capable of treating distorted lattice structures accurately. The calculated values of the lattice parameters of pure CaCuO2 lie within 3% of the experimentally measured values for the Sr-doped system Ca1.86Sr0.14CuO2. The computed electronic structures and the density of states are quite similar to those of the other oxide superconductors, except for their three-dimensional character because of the presence of strong coupling between the closely spaced CuO2 layers. The calculated frequencies for the k = 0 frozen phonons for undoped CaCuO2 are quite close to the measured data for Sr-doped CaCuO2.