Abstract
We present a systematic density functional theory (DFT) plus Hubbard study of structural trends and the stability of different magnetically ordered states across the rare-earth nickelate series, , with from Lu to La. In particular, we investigate how the magnetic order, the change of the rare-earth ion, and the Hubbard interaction are affecting the bond-length disproportionation between the nickel sites. Our results show that structural parameters can be obtained that are in very good agreement with present experimental data and that is in principle able to capture the most important structural trends across the nickelate series. However, the amplitude of the bond-length disproportionation depends very strongly on the specific value used for the Hubbard parameter and also on the type of magnetic order imposed in the calculation. Regarding the relative stability of different magnetic orderings, a realistic antiferromagnetic order, consistent with the experimental observations, is favored for small values and becomes more and more favorable compared to the ferromagnetic state towards the end of the series (i.e., towards ). Nevertheless, it seems that the stability of the ferromagnetic state is generally overestimated within the calculations. Our work provides a profound starting point for more detailed experimental investigations and also for future studies using more advanced computational techniques such as, e.g., DFT combined with dynamical mean-field theory.
4 More- Received 13 July 2017
- Revised 25 September 2017
DOI:https://doi.org/10.1103/PhysRevB.96.165130
©2017 American Physical Society