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arXiv 2212.01475cond-mat.str-elcond-mat.mtrl-sci
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具有二次电子-声子相互作用的极化子

Polaron with Quadratic Electron-phonon Interaction

Stefano Ragni, Thomas Hahn, Zhongjin Zhang, Nikolay Prokof'ev, Anatoly Kuklov, Serghei Klimin, Matthew Houtput, Boris Svistunov, Jacques Tempere, Naoto Nagaosa,… 展开作者

Stefano Ragni, Thomas Hahn, Zhongjin Zhang, Nikolay Prokof'ev, Anatoly Kuklov, Serghei Klimin, Matthew Houtput, Boris Svistunov, Jacques Tempere, Naoto Nagaosa, Cesare Franchini, Andrey S. Mishchenko

摘要:

我们提出了第一个数值精确的研究与二次耦合的振子位移的极化子,使用两种替代方法的发展。我们的结果涵盖了反绝热和绝热制度和整个范围的电子-声子耦合$g_2$,从系统的稳定性阈值在有吸引力的$g_2=-1$任意强排斥在$g_2 \gg 1$。二次极化子的关键性质与线性极化子有很大的不同。它们(i)是不敏感的,甚至大的二次耦合,除了在反绝热极限附近的阈值不稳定的吸引力;(ii)只依赖于绝热比,但不敏感的电子色散和空间尺寸;(iii)功能弱的晶格变形,即使在不稳定点。我们的结果是直接相关的性质,在低密度的极性材料,包括最近的建议,其超导状态的电子。

英文摘要:

We present the first numerically exact study of a polaron with quadratic coupling to the oscillator displacement, using two alternative methodological developments. Our results cover both anti-adiabatic and adiabatic regimes and the entire range of electron-phonon coupling $g_2$, from the system's stability threshold at attractive $g_2=-1$ to arbitrary strong repulsion at $g_2 \gg 1$. Key properties of quadratic polarons prove dramatically different from their linear counterparts. They (i) are insensitive even to large quadratic coupling except in the anti-adiabatic limit near the threshold of instability at attraction; (ii) depend only on the adiabatic ratio but are insensitive to the electron dispersion and dimension of space; (iii) feature weak lattice deformations even at the instability point. Our results are of direct relevance to properties of electrons at low densities in polar materials, including recent proposals for their superconducting states.

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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