Structural, dynamical, and electronic properties ofCaCuO2

Abstract

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-${\mathit{T}}_{\mathit{c}}$ oxide superconductors, i.e., ${\mathrm{CaCuO}}_{2}$. 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 ${\mathrm{CaCuO}}_{2}$ lie within 3% of the experimentally measured values for the Sr-doped system ${\mathrm{Ca}}_{1.86}$${\mathrm{Sr}}_{0.14}$${\mathrm{CuO}}_{2}$. 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 ${\mathrm{CuO}}_{2}$ layers. The calculated frequencies for the k=0 frozen phonons for undoped ${\mathrm{CaCuO}}_{2}$ are quite close to the measured data for Sr-doped ${\mathrm{CaCuO}}_{2}$.