Orbital antiferromagnetism in coupled planar systems

Abstract

A realistic model for the electronic structure of ${\mathrm{SrRuO}}_{3}$ is examined to determine the possibility of orbital antiferromagnetic order in this material. By calculating the susceptibility to orbital and spin antiferromagnetic order, it is shown that the band structure of ${\mathrm{SrRuO}}_{3}$ serves to destabilize the N\'eel ordered state and that the susceptibility to orbital antiferromagnetic order is larger over a range of doping. The resultant orbital antiferromagnetic state consists of coupled two-dimensional planes. The effect of the coupling on the planar system is calculated; the energy shifts of different configurations depend only on the total current in the sample and are linear in this quantity. An orbital antiferromagnetic ground state is found which has no net current flowing along the bonds.