Oral: Electron-K-Phonon Interaction in Twisted Bilayer Graphene

We develop an analytic theory to describe the interaction between electrons and K-phonons and study its influence on superconductivity in the bare bands of twisted bilayer graphene (TBG). We find that, due to symmetry and the two-center approximation, only one optical K phonon (∼ 160meV) of graphene is responsible for inter-valley electron-phonon interaction. This phonon has recently been found in angular-resolved photo-emission spectroscopy to be responsible for replicas of the TBG flat bands. We analyzed the properties of replica bands induced by electron-K-phonon in TBG and compared it with the experimental observations. By projecting the interaction to the TBG flat bands, we perform the full symmetry analysis of phonon-mediated attractive interaction and pairing channels in the Chern basis and show that several channels are guaranteed to have gapless order parameters. The gap equation from the phonon-mediated attractive interaction is investigated to support our symmetry analysis.