Electronic structure and magnetism of Sr3Ru2O7 - art. no. 165101

The electronic structure of layered Sr3Ru2O7 in its orthorhombic structure is investigated using density functional calculations. The band structure n ear the Fermi energy, consists of Ru t(2g) states hybridized with O p orbit als. The gz and st bands, which are largely responsible for the nesting rel ated antiferromagnetic spin fluctuations in Sr(2)Ru4 split pairwise into ev en and odd combinations due to the interlayer coupling reducing the strengt h of the nesting. The xy bands show much less interplanar coupling as expec ted, and also less c-axis dispersion, so that the barrel-like sections are largely intact compared to the single layer material. The zone folding due to orthorhombicity yields small cylindrical lens shaped Fermi surfaces cent ered at the midpoints of the former tetragonal Gamma -X lines. Fixed spin m oment calculations indicate that tetragonal Sr3Ru2O7 is borderline ferromag netic but that orthorhombicity favors magnetism via a substantial magnetoel astic coupling. These results are related to experimental observations part icularly in regard to magnetic properties.