The electronic structures and magnetic properties of perovskite ruthenates from constrained orbital-hybridization calculations

We introduce a method to analyze the effect of hybridization by shifting the corresponding atomic levels using external potentials. Based on this approach, we study perovskite ruthenates, and unambiguously identify that the covalency between the A-site cation and the O ion modifies the Ru-O hybridization and change the density of state at the Fermi level, consequently affecting the magnetic properties significantly. We also study the effect of pressure and reveal that hydrostatic pressure has a small effect on the Ru-O-Ru bond angle of SrRuO(3), while it decreases the Ru-O length and increase the band width significantly. Therefore, the magnetic-ordering temperature will decrease monotonically with pressure. Copyright (C) EPLA, 2010