Spin transport in the Néel and collinear antiferromagnetic phase of the two dimensional spatial and spin anisotropic Heisenberg model on a square lattice
Spin transport in the Néel and collinear antiferromagnetic phase of the two dimensional spatial and spin anisotropic Heisenberg model on a square lattice
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方晶格上二维空间和自旋各向异性海森堡模型的尼尔自旋输运和共线反铁磁相
DOI：
10.1140/epjb/e2012-30708-7
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
D. Yao
中科院分区：
文献类型：
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作者：
Zewei Chen;T. Datta;D. Yao
本文分析和比较了空间各向异性和自旋各向异性对二维正方晶格上S = 1/2海森堡量子磁体自旋电导率的影响。我们探讨了Néel反铁磁（AF）相和共线反铁磁（CAF）相的模型。我们发现，在海森堡模型中的自旋各向异性的影响相比，在AF阶段的空间各向异性不抑制零温度的自旋电导率在零频率限制，而不是它增强it. In的CAF阶段（在非相互作用近似），零频率的自旋电导率有一个有限的值，这是抑制的空间各向异性参数的增加。此外，CAF阶段显示在AF阶段中未看到的自旋电导率的尖峰。我们还探讨了有限的温度影响的Drude重量在AF阶段（无碰撞近似）。我们发现，提高空间各向异性增加的Drude权值和增加自旋各向异性降低的Drude权值。基于这些研究，我们得出结论，具有空间各向异性的反铁磁体是更好的自旋导体比自旋各向异性在零温度和有限温度。
We analyze and compare the effect of spatial and spin anisotropy on spin conductivity in a two dimensional S = 1/2 Heisenberg quantum magnet on a square lattice. We explore the model in both the Néel antiferromagnetic (AF) phase and the collinear antiferromagnetic (CAF) phase. We find that in contrast to the effects of spin anisotropy in the Heisenberg model, spatial anisotropy in the AF phase does not suppress the zero temperature regular part of the spin conductivity in the zero frequency limit–rather it enhances it. In the CAF phase (within the non-interacting approximation), the zero frequency spin conductivity has a finite value, which is suppressed as the spatial anisotropy parameter is increased. Furthermore, the CAF phase displays a spike in the spin conductivity not seen in the AF phase. We also explore the finite temperature effects on the Drude weight in the AF phase (within the collisionless approximation). We find that enhancing spatial anisotropy increases the Drude weight value and increasing spin anisotropy decreases the Drude weight value. Based on these studies, we conclude that antiferromagnets with spatial anisotropy are better spin conductors than those with spin anisotropy at both zero and finite temperatures.