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arXiv · 2104.02277

$x$-[Pd(dmit)$_2$]$_2$ as a quasi-1D, scalene Heisenberg model

E. P. Kenny·A. C. Jacko·B. J. Powell
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Abstract

From first principles, we calculate the Heisenberg interactions between neighboring dimers in several compounds within the Et$_{n}$Me$_{4-n}X$[Pd(dmit)$_2$]$_2$ (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 that frustration further enhances this quasi-one-dimensionality. We calculate the N\'eel ordering temperature via the chain random phase approximation (CRPA). 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 N\'eel ordering temperatures are in good agreement with the experimentally measured values for most compounds.

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E. P. Kenny, A. C. Jacko, B. J. Powell. 2021-04-06. $x$-[Pd(dmit)$_2$]$_2$ as a quasi-1D, scalene Heisenberg model. https://doi.org/10.1103/physrevmaterials.5.084412

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