LDA + Negative U Solves a Puzzle of too Large Calculated Magnetic Moment in Iron-based Superconductor LaFeAsO_{1-x}F_x
| dc.creator | Nakamura, H. | |
| dc.creator | Hayashi, N. | |
| dc.creator | Nakai, N. | |
| dc.creator | Machida, M. | |
| dc.date | 2008-06-30 | |
| dc.date.accessioned | 2026-07-07T09:47:25Z | |
| dc.date.available | 2026-07-07T09:47:25Z | |
| dc.description | A puzzle in the iron-based superconductor LaFeAsO_{1-x}F_x is that the magnetic moment obtained by first-principle electronic structure calculations is unexpectedly much larger than the experimentally observed one. For example, the calculated value is ~ 2.0 μ_B in the mother compound, while it is ~ 0.3 μ_B in experiments. We find that the puzzle is solved within the framework LDA + U by expanding the U value into a slightly negative range. We show U dependence of the obtained magnetic moment in both the undoped x=0.0 and doped x = 0.125. These results reveal that the magnetic moment is drastically reduced when entering to the slightly negative range of U. Moreover, the negative U well explains other measurement data, e.g., lattice constants and electronic DOS at the Fermi level. We discuss possible origins of the negative U in these compounds. | |
| dc.description | 5 pages, 4 figures | |
| dc.identifier | https://arxiv.org/abs/0806.4804 | |
| dc.identifier | http://arxiv.org/abs/0806.4804 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/163871 | |
| dc.subject | Superconductivity | |
| dc.title | LDA + Negative U Solves a Puzzle of too Large Calculated Magnetic Moment in Iron-based Superconductor LaFeAsO_{1-x}F_x | |
| dc.type | text |