Towards exact solutions for the superconducting T-c induced by electron-phonon interaction

Article

关键词: DENSITY-WAVE CORRELATIONS;    GAUGE-INVARIANCE;    LATTICE-VIBRATIONS;    HOLSTEIN MODEL;    MONOLAYER FESE;    IDENTITIES;    BREAKDOWN;    VACUUM;    POINT;   

DOI  :  10.1103/PhysRevB.103.094501

来源: SCIE

【 摘 要 】

Electron-phonon interaction plays an important role in metals and can lead to superconductivity and other instabilities. Previous theoretical studies on superconductivity are largely based on the Migdal-Eliashberg theory, which neglects all the vertex corrections to electron-phonon coupling and breaks down in many unconventional superconductors. Here, we go beyond the Migdal-Eliashberg approximation and develop a nonperturbative Dyson-Schwinger equation approach to deal with the superconducting transition. Remarkably, we take into account all the vertex corrections by solving two coupled Ward-Takahashi identities derived from two global U(1) symmetries and rigorously prove that the fully renormalized electron propagator satisfies a self-closed integral equation that is directly amenable to numerical computations. Our approach works equally well in the weak and strong coupling regimes and provides an efficient method to determine superconducting T-c and other quantities. As an application, our approach is used to investigate the high-T-c superconductivity in one-unit-cell FeSe/SrTiO3.

【 授权许可】

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