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arXiv 1407.3205cond-mat.mtrl-scicond-mat.str-el
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NaMnF3钙钛矿-后钙钛矿压力转变的振动和非共线磁性的第一性原理研究

First-Principles study of vibrational and non-collinear magnetic properties of the perovskite to post-perovskite pressure transition of NaMnF3

A. C. Garcia-Castro, A. H. Romero, E. Bousquet

摘要:

我们进行了第一性原理研究的结构,振动,电子和磁性的NaMnF 3下施加各向同性压力的性质。我们发现NaMnF 3在8 GPa下经历了从Pnma畸变钙钛矿结构向Cmcm后钙钛矿结构的重构相变。这通过Mn-F-Mn键的突然变化来证实,其中晶体从Pnma相中的角共享八面体变为Cmcm相中的边缘共享八面体。磁有序也从Pnma相中的G型反铁磁有序变为Cmcm相中的C型反铁磁有序。有趣的是,我们发现高自旋d轨道填充保持在相变,这在已知的磁性后钙钛矿结构中从未观察到。我们还发现了一个高度非共线磁有序的Cmcm后钙钛矿相,驱动一个大的铁磁倾斜的自旋。我们讨论了这些结果的有效性与在我们的研究中使用的GGA+U交换相关功能的U和J参数,并得出结论,大的自旋倾斜是一个有前途的性能后钙钛矿氟化物。

英文摘要:

We performed a first-principles study of the structural, vibrational, electronic and magnetic properties of NaMnF3 under applied isotropic pressure. We found that NaMnF3 undergoes a reconstructive phase transition at 8 GPa from the Pnma distorted perovskite structure toward the Cmcm post-perovskite structure. This is confirmed by a sudden change of the Mn-F-Mn bondings where the crystal goes from corner shared octahedra in the Pnma phase to edge shared octahedra in the Cmcm phase. The magnetic ordering also changes from a G-type antiferromagnetic ordering in the Pnma phase to a C-type antiferromagnetic ordering in the Cmcm phase. Interestingly, we found that the high-spin d-orbital filling is kept at the phase transition which has never been observed in the known magnetic post-perovskite structures. We also found a highly non-collinear magnetic ordering in the Cmcm post-perovskite phase that drives a large ferromagnetic canting of the spins. We discuss the validity of these results with respect to the U and J parameter of the GGA+U exchange correlation functional used in our study and conclude that large spin canting is a promising property of the post-perovskite fluoride compounds.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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