Ab-initio calculation of exchange interactions in YMnO3
Ab-initio calculation of exchange interactions in YMnO3
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DOI：
10.1016/j.commatsci.2008.01.028
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发表时间：
2008-11
影响因子：
3.3
通讯作者：
P. Novák;I. Chaplygin;G. Seifert;S. Gemming;R. Laskowski
中科院分区：
文献类型：
--
作者：
P. Novák;I. Chaplygin;G. Seifert;S. Gemming;R. Laskowski
对所选自旋构型的ymno3进行了基于密度泛函的电子结构计算，并根据总能量的差值确定了交换积分。为了改善对Mn强相关三维电子的描述，采用了LDA+U方法。最强的交换相互作用发生在最近邻的Mn自旋之间，次近邻之间的相互作用弱一个数量级以上。交换积分与参数U成反比，表明超交换相互作用占主导地位。由于最近的锰的三角形排列，磁性在几何上受到挫折，因此双二次或/和各向异性交换可能是重要的。非共线自旋结构的计算表明双二次交换相互作用的存在。
The density functional based calculations of the electronic structure of YMnO3are performed for selected spin configurations and from the differences of the total energies the exchange integrals are determined. To improve the description of strongly correlated 3d electrons of Mn the LDA+U method is employed. The strongest exchange interaction is found between the nearest neighbor Mn spins, the interaction between the next nearest neighbors being more than order of magnitude weaker. Exchange integrals are inversely proportional to the parameter U, pointing to the dominance of the superexchange interaction. Due to the triangular arrangement of the nearest Mn the magnetism is geometrically frustrated so that biquadratic or/and anisotropic exchange may be important. The calculation of non-collinear spin structures indicates the presence of the biquadratic exchange interaction.