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arXiv 2105.06362cond-mat.mtrl-sci
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准一维有机导体(TMTTF)$_2$ NO $_3$的电荷序相变

Charge-order phase transition in the quasi one-dimensional organic conductor (TMTTF)$_2$NO$_3$

Lena Nadine Majer, Björn Miksch, Guilherme Gorgen Lesseux, Gabriele Untereiner, Martin Dressel

摘要:

低维有机导体显示出丰富的相图,尽管付出了各种努力,仍然有一些未开发的区域。电荷有序相存在于(TMTTF)$_2 X$家族的许多化合物中,通常研究它们独特的电子性质。然而,乍一看,对自旋排列的影响是预料不到的。在这里,我们报告的温度和角度相关的电子自旋共振(ESR)测量准一维有机导体(TMTTF)$_2$ NO $_3$。我们发现,(TMTTF)$_2$ NO $_3$化合物在低于约$T_\text{CO}=250\pm 10$ K时,ESR谱线宽度呈现出一种具有双倍周期性($ab'$ -平面)的特殊各向异性.这种行为与相关化合物(TMTTF)$_2 X$($X$ = PF $_6$、SbF $_6$和AsF $_6$)中的观察结果相似,其中它被归因于电荷有序状态下磁不等价位点的弛豫过程。对于结构类似物(TMTTF)$_2$ ClO $_4$,已知其不存在电荷有序,未观察到ESR信号的这种角度依赖性。因此,我们的ESR测量使我们得出结论,在低于$T_\text{CO} \approx 250$ K的温度下,标题化合物中的电荷序相是稳定的。

英文摘要:

Low-dimensional organic conductors show a rich phase diagram, which has, despite all efforts, still some unexploed regions. Charge ordered phases present in many compounds of the (TMTTF)$_2 X$ family are typically studied with their unique electronic properties in mind. An influence on the spin arrangement is, however, not expected at first glance. Here, we report temperature and angle dependent electron spin resonance (ESR) measurements on the quasi one-dimensional organic conductor (TMTTF)$_2$NO$_3$. We found that the (TMTTF)$_2$NO$_3$ compound develops a peculiar anisotropy with a doubled periodicity ($ab'$-plane) of the ESR linewidth below about $T_\text{CO}=250\pm 10$ K. This behavior is similar to observations in the related compounds (TMTTF)$_2 X$ ($X$ = PF$_6$, SbF$_6$ and AsF$_6$), where it has been attributed to relaxation processes of magnetically inequivalent sites in the charge-ordered state. For the structural analogous (TMTTF)$_2$ClO$_4$, known for the absence of charge order, such angular dependence of the ESR signal is not observed. Therefore, our ESR measurements lead us to conclude that a charge-order phase is stabilized in the title compound below $T_\text{CO} \approx 250$ K.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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