Abstract
In order to explore the effects of structural geometry on the properties of correlated metals we investigate the magnetic properties of cubic () and hexagonal () . While the variant of is ferromagnetic below 60 K, the phase does not show any long-range magnetic order, though, there is experimental evidence of short-range antiferromagnetic correlations. Employing a combination of computational tools, namely, density-functional theory and dynamical mean-field theory calculations, we probe the origin of contrasting magnetic properties of in the and structures. Our study reveals that the difference in connectivity of octahedra in the two phases results in different Ru-O covalency, which in turn influences substantially the strengths of screened interaction values for Hubbard and Hund's rule . With estimated and values, the phase turns out to be a ferromagnetic metal, while the phase shows paramagnetic behavior with vanishing ordered moments. However, this paramagnetic phase bears signatures of antiferromagnetic correlations, as confirmed by a calculation of the magnetic susceptibility. We find that the phase is found to be at the verge of antiferromagnetic long-range order, which can be stabilized upon slight changes of screened Coulomb parameters and , opening up the possibility of achieving a rare example of an antiferromagnetic metal.
1 More- Received 10 November 2021
- Revised 20 April 2022
- Accepted 27 May 2022
DOI:https://doi.org/10.1103/PhysRevB.105.235106
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