arXiv 1502.033512015-02-11cond-mat.mtrl-scicond-mat.str-el

First-principles study of structurally modulated multiferroic CaMn$_7$O$_{12}$

Kun Cao, Roger D. Johnson, Natasha Perks, Feliciano Giustino, Paolo G. Radaelli

DOI：: 10.1103/PhysRevB.91.064422

英文摘要：

We study the electronic and magnetic structures of multiferroic CaMn$_7$O$_{12}$ by first-principle calculations, based on the experimentally determined modulated crystal structure. We confirm the presence of a 3$d$ orbital modulation of the Mn2 (Mn$^{3+}$) sites, previously inferred from the Jahn-Teller crystal distortions. Our results indicate that in the multiferroic phase the magnetic structure of the Mn3 (Mn$^{4+}$) sites is anharmonically modulated via orbitally-mediated coupling with the structural modulation, and that the Dzyaloshinskii-Moriya and exchange striction mechanisms contribute equally to the polarization

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