Electronic and magnetic properties of LaRuO3 and LaFeO3: Orbital order and canted antiferromagnetism

Abstract

The electronic and magnetic structures of LaRuO3 has been attracted much attention. The remaining problem is to identify and understand the ground-state of LaRuO3. To clarify the situation we chose the LaFeO3 as a comparison and evaluated the ground-state properties by first-principles calculations. We found the LaRuO3 was GdFeO3-type Jahn-Teller distorted for the longer Ru-O bonds. The electronic structure calculations identified the LaRuO3 was a G-type antiferromagnetic insulator. The low spin eg0t2g5 population and the RuO6 octahedron distortion induced the LaRuO3 orbital ordered which was found from the spin charge density. We also found the onsite Coulomb interactions U regulated the ground-state and the spin-orbital coupling persisted the orbital order. The simulations of magnetic properties suggested the LaRuO3 was canted antiferromagnetic ordered with a lower Neel temperature of 90 K compared to the 802 K of LaFeO3. The difference between LaFeO3 and LaRuO3 revealed that the 4d electrons in LaRuO3 introduced an orbital freedom.