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arXiv 1310.7810cond-mat.str-el
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蜂窝晶格上的价键液体

A valence bond liquid on the honeycomb lattice

Simon A. J. Kimber, I. I. Mazin, Juan Shen, Harald O. Jeschke, Sergey V. Streltsov, Dimitri N. Argyriou, Roser Valenti, Daniel I. Khomskii

摘要:

蜂窝晶格材料Li2RuO3在冷却到270 ℃以下时发生Ru 4+阳离子的二聚化,此时磁化率消失。我们使用密度泛函理论计算表明,这反映了一个“价键晶体”的形成,具有很强的键的反折。在变暖,X射线衍射表明,离散的三重对称性平均恢复,和二聚化明显消失。相比之下,使用高能X射线的局部结构测量表明,无序二聚体在纳米级上至少可以存活到650 ℃。因此,Li2RuO3的高温相是价键液体的一个例子,其中热波动驱动不同二聚体覆盖率之间的共振,这是通常与高T $_c$铜酸盐相关讨论的共振价键状态的经典类似物。

英文摘要:

The honeycomb lattice material Li2RuO3 undergoes a dimerization of Ru4+ cations on cooling below 270C, where the magnetic susceptibility vanishes. We use density functional theory calculations to show that this reflects the formation of a 'valence bond crystal', with a strong bond disproportionation. On warming, x-ray diffraction shows that discrete three-fold symmetry is regained on average, and the dimerization apparently disappears. In contrast, local structural measurements using high-energy x-rays, show that disordered dimers survive at the nanoscale up to at least 650C. The high temperature phase of Li2RuO3 is thus an example of a valence bond liquid, where thermal fluctuations drive resonance between different dimer coverages, a classic analogue of the resonating valence bond state often discussed in connection with high T$_c$ cuprates.

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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