Eliashberg theory of the Jahn-Teller-Hubbard model
Eliashberg theory of the Jahn-Teller-Hubbard model
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DOI：
10.1103/physrevb.105.214516
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发表时间：
2022-03
影响因子：
3.7
通讯作者：
Yoshikuni Kaga;P. Werner;S. Hoshino
中科院分区：
文献类型：
--
作者：
Yoshikuni Kaga;P. Werner;S. Hoshino
我们研究了耦合到局域Jahn-Teller声子的多轨道Hubbard模型来研究富勒烯中实现的超导态。一个弱耦合的方法结合本地自能近似。除了正常和异常的自能的电子，我们认为声子自能，它允许一个自洽的治疗的能量。通过数值计算，详细研究了自能及其特征系数，如重整化因子和阻尼的频率依赖性。阐明了各向异性声子对超导态的稳定起着重要的作用。通过比较完整的结果与那些没有声子自能，我们表明，超导电性是稳定的声子频率的软化。电子涨落的影响也被考虑，这导致耦合到轨道，在电子气中的等离子体激元的模拟。这种额外的贡献进一步稳定了超导状态。
We study a multiorbital Hubbard model coupled to local Jahn-Teller phonons to investigate the superconducting state realized in fullerides. A weak-coupling approach is employed in combination with a local self-energy approximation. In addition to the normal and anomalous self-energies of the electrons, we consider the phonon self-energy, which allows a self-consistent treatment of the energetics. The frequency dependence of the self-energies and their characteristic coefficients, such as renormalization factors and dampings, are investigated in detail using numerical calculations. It is clarified that the anisotropic phonons play an important role in the stabilization of the superconducting state. By comparing the full results to those without phonon self-energies, we show that the superconductivity is stabilized by the softening of the phonon frequency. The effects of electronic fluctuations are also considered, which leads to the coupling to orbitons, an analog of plasmons in the electron gas. This additional contribution further stabilizes the superconducting state.