A theoretical study of the magnetic properties of the infinite-layer superconductor

Abstract

The antiferromagnetic state of the undoped CaCuO2 superconductor cannot be easily obtained by a first principles calculation. In this article a simple model is presented to approximately calculate this state using linearized augmented plane wave based on density functional theory. By studying the density of states it is shown that the antiferromagnetism is originated exclusively in the Cu:d orbitals and that the major effect is around the Fermi energy. This model is later applied to (YxCa1-x)CuO2 and (NdxCa1-x)CuO2. For the yttrium compound at "low" doping (25%) antiferromagnetism diminishes but is not destroyed, but at higher doping (50%) it is destroyed. For the neodymium compound the main feature at the Fermi energy is the Nd:4f, which is so strong that destroys the antiferromagnetism of copper atoms. (C) 2000 John Wiley & Sons, Inc.