Electronic structure and exchange interactions in BaVS3
Electronic structure and exchange interactions in BaVS3
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BaVS3 中的电子结构和交换相互作用
DOI：
10.1103/physrevb.70.035110
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发表时间：
2004
期刊：
影响因子：
--
通讯作者：
G. Guo
中科院分区：
文献类型：
--
作者：
Xue;G. Guo
本文采用广义梯度近似下的密度泛函方法，利用投影增广波方法研究了准一维硫化物的电子结构和自旋交换相互作用。在此基础上，我们还考虑了在位库仑排斥效应，从而解释了关联效应对电子结构的影响。我们发现在高温六方结构中，部分填充的导带（包括宽导带和两个双导带）对的电导率有贡献，表明电子输运的各向异性较弱.此外，我们的能带结构计算预测了一个绝缘的基态与一个狭窄的gap为在低温正交结构，从而表明Mott-Hubbard机制的低温绝缘行为。我们的基态自旋配置在低温阶段的总能量分析表明，与链内铁磁自旋安排和链间反铁磁自旋安排，是通过硫轨道的超交换机制一致的磁性结构是首选。我们还通过将计算的总能量映射到海森堡自旋模型上来估计交换积分的值。发现较强的交换相互作用是铁磁链内耦合，而较弱的反铁磁链间耦合则发生在沿着轴。结果表明，该样品具有明显的磁各向异性，并导致了所观察到的准一维磁特征。这表明自旋自由度和电荷自由度的分离是异常性质的可能原因，例如，的三维电子输运和准一维磁性。
The electronic structure and spin exchange interactions of a quasi-one-dimensional sulfidehave been studied within the density functional theorywith the generalized gradient approximationusing the projected augmented wavemethod. The on-site Coulomb repulsion has also been taken into account in theapproach to unravel the correlation effects on the electronic structure. We found that in the high-temperature hexagonal structure the partially filledconduction bands including the broadand two narroworbitals contribute to the conductivity of, suggesting a weak anisotropy in the electronic transport. Furthermore, ourband structure calculations predict an insulating ground state with a narrow gap offorin the low-temperatureorthorhombic structure, thereby indicating the Mott-Hubbard mechanism for the low-temperature insulating behavior. Our total energy analyses of the ground-state spin configuration in the low-temperature phases show that the magnetic structure with an intrachain ferromagnetic spin arrangement and an interchain antiferromagnetic spin arrangement that is consistent with a superexchange mechanism through sulfurorbitals is preferred. We have also estimated the values of exchange integrals by mapping the calculated total energies onto the Heisenberg spin model. It is found that the stronger exchange interaction is ferromagnetic intrachain coupling, while the weaker antiferromagnetic interchain coupling occurs along theaxis. A substantial magnetic anisotropy is found and results in the observed quasi-1D magnetic character in. This suggests the separation of the spin and charge degrees of freedom as a possible cause of the anomalous properties, e.g., the 3D electronic transport and the quasi-1D magnetism of.