Leading interactions in the β − Sr V 6 O 15 compound
Leading interactions in the β − Sr V 6 O 15 compound
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β − Sr V 6 O 15 化合物中的主要相互作用
DOI：
10.1103/physrevb.71.075119
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发表时间：
2005
影响因子：
3.7
通讯作者：
M. Lepetit
中科院分区：
文献类型：
--
作者：
M. Doublet;M. Lepetit
研究表明，$\ensuremath{\beta}\text{\ensuremath{-}}A{\mathrm{V}}_{6}{\mathrm{O}}_{15}$族化合物(A=Mathrm{SR}，Mathrm{Ca}，mathrm{Na}\dots})的电子结构是基于弱相互作用的两腿梯形结构，而不是人们可以从其晶体结构中得到的锯齿链模型。基于扩展的H“uckel紧束缚计算，对自旋二聚体进行了分析，确定了室温$\ensuremath{\beta}\text{\ensuremath{-}}\mathrm{Sr}{\mathrm{V}}_{6}{\mathrm{O}}_{15}$相中主要转移和磁相互作用的结构。提出了两个对应于不同电荷/自旋顺序的两个不同的两腿阶梯来描述这些一维Beta类系统。这些反铁磁梯被包装成“IPN”几何形状，并通过弱的反铁磁性相互作用相互耦合。这种主要相互作用的排列解释了一维数学型相和二维数学型相(如著名的${\ensuremath{\alpha}}^{\ensuremath{‘}}\text{\ensuremath{-}}\mathrm{Na}{\mathrm{V}}_{2}{\mathrm{O}}_{5}$系统)的光学电导和拉曼光谱惊人的相似之处。
The present study shows that the electronic structure of the $\ensuremath{\beta}\text{\ensuremath{-}}A{\mathrm{V}}_{6}{\mathrm{O}}_{15}$ family of compounds $(A=\mathrm{Sr},\mathrm{Ca},\mathrm{Na}\dots{})$ is based on weakly interacting two-leg ladders, in contrast with the zig-zag chain model one could expect from their crystal structure. Spin dimer analysis, based on extended H\"uckel tight-binding calculations, was performed to determine the structure of the dominant transfer and magnetic interactions in the room temperature $\ensuremath{\beta}\text{\ensuremath{-}}\mathrm{Sr}{\mathrm{V}}_{6}{\mathrm{O}}_{15}$ phase. Two different two-legs ladders, associated with different charge/spin orders are proposed to describe these one-dimensional $\ensuremath{\beta}$-type systems. The antiferromagnetic ladders are packed in an ``IPN'' geometry and coupled to each other through weak antiferromagnetic interactions. This arrangement of the dominant interactions explains the otherwise surprising similarities of the optical conductivity and Raman spectra for the one-dimensional $\ensuremath{\beta}$-type phases and the two-dimensional $\ensuremath{\alpha}$-type ones such as the well-known ${\ensuremath{\alpha}}^{\ensuremath{'}}\text{\ensuremath{-}}\mathrm{Na}{\mathrm{V}}_{2}{\mathrm{O}}_{5}$ system.