Electron-phonon driven superconductivity: do we really have a microscopic understanding of it?

电子声子驱动的超导：我们真的对它有微观的了解吗？

• 批准号: 203396-2012
• 负责人: Marsiglio, Frank
• 金额: $ 1.46万
• 依托单位: University of Alberta
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=569944
• 关键词: Electron; phonon; driven; superconductivity; do

100 years after the discovery of superconductivity in elemental Mercury, we have innumerable families of superconducting materials, each of which seems to have little in common with one another. The phenomenon of superconductivity is all about the movement of charge, and even our understanding of the mechanism for this remarkable state of matter, at least for so-called conventional superconductors, is about pairing through charge fluctuations. In contrast, for newer superconductors, many of the current ideas about the mechanism involved center around `spin fluctuations' as the `pairing glue'. But to understand how electrons can both carry the current and provide the pairing mechanism, we propose to go back and gain a deeper understanding of how electrons pair in the conventional mechanism. The historical theory (Eliashberg) explains what happens to the electrons, but never really explains simultaneously what happens to the phonons, as they interact with the electrons. In this sense it remains a phenomenology, and we propose to provide a truly microscopic description of the superconducting state, through advanced theoretical techniques. In this way, not only will we gain insights into how the conventional superconductor works, but we should be better equipped to deal with the more difficult problem of understanding an unconventional superconductor where the carriers and the pairing glue appear to originate from the same electrons. The goal is that a deeper understanding of the mechanism of superconductivity will aid material scientists in the search for higher temperature superconductivity.

在元素汞中发现超导性 100 年后，我们拥有了无数的超导材料家族，每一种材料似乎彼此之间都没有什么共同点。超导现象全都与电荷的运动有关，甚至我们对这种非凡物质状态的机制的理解，至少对于所谓的传统超导体来说，也是通过电荷波动配对的。相比之下，对于较新的超导体，当前有关其机制的许多想法都集中在作为“配对粘合剂”的“自旋涨落”上。 但为了了解电子如何携带电流并提供配对机制，我们建议返回并更深入地了解电子如何在传统机制中配对。历史理论（Eliashberg）解释了电子发生的情况，但从未真正同时解释声子与电子相互作用时发生的情况。从这个意义上说，它仍然是一种现象学，我们建议通过先进的理论技术提供超导态的真正微观描述。 通过这种方式，我们不仅可以深入了解传统超导体的工作原理，而且应该能够更好地处理更困难的问题，即理解非常规超导体，其中载流子和配对胶似乎源自相同的电子。目标是更深入地了解超导机制将有助于材料科学家寻找更高温度的超导性。