From first principles, we calculate the Heisenberg interactions between neighboring dimers in several compounds within the ${\mathrm{Et}}_n{\mathrm{Me}}_{4-n}X{\left[{\mathrm{Pd}\left(\mathrm{dmit}\right)}_2\right]}_2$ (Et = ethyl, Me = methyl, dmit = 2-thioxo-1,3-dithiole-4,5-dithiolate) family using an atomistic approach, with broken-symmetry density functional theory. In all materials, we find a scalene triangular model where the strongest exchange coupling along one crystallographic axis is up to three times larger than the others and where the frustration further enhances this quasi-one-dimensionality. We calculate the Néel ordering temperature via the chain random phase approximation. We show that the difference in the frustrated interchain couplings is equivalent to a single bipartite interchain coupling, favoring long-range magnetic order. We find that the Néel ordering temperatures are the same order of magnitude as the experimentally measured values for most compounds.

中文翻译：

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x−[Pd(dmit)2]2 作为准一维不等边线海森堡模型

根据第一原理，我们计算了几个化合物中相邻二聚体之间的海森堡相互作用 ${\mathrm{ET}}_n{我}_{4-n}X{\left[{钯\left(\mathrm{拒绝}\right)}_2\right]}_2$(Et = 乙基, Me = 甲基, dmit = 2-thioxo-1,3-dithiole-4,5-dithiolate) 族使用原子方法，具有破缺对称密度泛函理论。在所有材料中，我们发现了一个不等边三角形模型，其中沿着一个晶轴的最强交换耦合比其他晶轴大三倍，并且挫折进一步增强了这种准一维。我们通过链随机相位近似计算 Néel 排序温度。我们表明，受挫的链间耦合的差异相当于单个二分链间耦合，有利于长程磁序。我们发现 Néel 排序温度与大多数化合物的实验测量值处于同一数量级。