Jahn-Teller distortion and charge, orbital, and magnetic order in NaMn7 O12

Abstract

With the use of band structure calculations we demonstrate that previously reported [A. Prodi, Nat. Mater. 3, 48 (2004)1476-112210.1038/nmat1038] experimental crystal and magnetic structures for NaMn7O12 are inconsistent with each other. The optimization of the crystal lattice allows us to predict another crystal structure for the low temperature phase, which is qualitatively different from the one presented before. The AFM-CE type of magnetic order stabilizes the structure with elongated, not compressed, MnB3+O6 octahedra, excluding NaMn7O12 from the list of anomalous Jahn-Teller systems. The orbital correlations were shown to exist even in the cubic phase, while the charge order appears only in the low temperature distorted phase. © 2014 American Physical Society.