Coulomb interaction, phonons, and superconductivity in twisted bilayer graphene

The polarizability of twisted bilayer graphene, due to the combined effect of electron-hole pairs, plasmons, and acoustic phonons, is analyzed. The screened Coulomb interaction allows for the formation of Cooper pairs and superconductivity in a significant range of twist angles and fillings. The tendency toward superconductivity is enhanced by the coupling between longitudinal phonons and electron-hole pairs. Scattering processes involving large momentum transfers, Umklapp processes, play a crucial role in the formation of Cooper pairs. The magnitude of the superconducting gap changes among the different pockets of the Fermi surface.

Automated summary

The polarizability of twisted bilayer graphene, influenced by electron-hole pairs, plasmons, and acoustic phonons, allows for the formation of Cooper pairs and superconductivity through screened Coulomb interaction. The coupling between longitudinal phonons and electron-hole pairs enhances the tendency towards superconductivity. Umklapp processes involving large momentum transfers play a crucial role in the formation of Cooper pairs, resulting in varying magnitudes of the superconducting gap on the Fermi surface.