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arXiv 0907.1836cond-mat.supr-concond-mat.str-el
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TiSe2中的激子-声子相互作用和临界电荷序的超导电性

Exciton-phonon interactions and superconductivity bordering charge order in TiSe2

Jasper van Wezel, Paul Nahai-Williamson, Siddarth S. Saxena

摘要:

晶格模式和电荷之间的强耦合导致在诸如过渡金属二硫属化物的材料中形成电荷密度波,这也可以在相同的材料中引起超导性,由主导电荷有序状态的相同激子或声子模式介导。这种超导相最近已经在例如TiSe 2中被观察到,无论是在与铜的嵌入时还是在压力下的原始材料中。在这里,我们调查激子形成和电子-声子耦合的相互作用在一个简化的模型描述。我们发现,结合激子-声子模式先前建议驱动的电荷密度波不稳定性在TiSe 2也负责在其超导区域的电子配对。基于这些结果,它建议,这两个观察到的圆顶形成一个单一的超导相的一部分。我们还研究了从抑制电荷序中产生的量子临界涨落对超导区正上方输运性质的影响,并将我们的发现与已有的实验结果进行了比较。

英文摘要:

The strong coupling between lattice modes and charges which leads to the formation of charge density waves in materials such as the transition-metal dichalcogenides may also give rise to superconductivity in the same materials, mediated by the same exciton or phonon modes that dominate the charge ordered state. Such a superconducting phase has recently been observed for example in TiSe2, both upon intercalation with Copper and in the pristine material under pressure. Here we investigate the interplay of exciton formation and electron-phonon coupling within a simplified model description. We find that the combined exciton-phonon modes previously suggested to drive the charge density wave instability in TiSe2 are also responsible for the pairing of electrons in its superconducting regions. Based on these results, it is suggested that both of the observed domes form part of a single superconducting phase. We also study the effect of the quantum critical fluctuations emerging from the suppressed charge order on the transport properties directly above the superconducting region, and compare our finding with reported experimental results.

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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