1 research outputs found
Superconductivity from spin fluctuations and long-range interactions in magic-angle twisted bilayer graphene
Magic-angle twisted bilayer graphene (MATBG) has been extensively explored
both theoretically and experimentally as a suitable platform for a rich and
tunable phase diagram that includes ferromagnetism, charge order, broken
symmetries, and unconventional superconductivity. In this work, we investigate
the intricate interplay between long-range electron-electron interactions, spin
fluctuations, and superconductivity in MATBG. By employing a low-energy model
for MATBG that captures the correct shape of the flat bands, we explore the
effects of short- and long-range interactions on spin fluctuations and their
impact on the superconducting (SC) pairing vertex in the Random Phase
Approximation (RPA). We find that the SC state is notably influenced by the
strength of long-range Coulomb interactions. Interestingly, our RPA
calculations indicate that there is a regime where the system can traverse from
a magnetic phase to the SC phase by \emph{increasing} the relative strength of
long-range interactions compared to the on-site ones. These findings underscore
the relevance of electron-electron interactions in shaping the intriguing
properties of MATBG and offer a pathway for designing and controlling its SC
phase.Comment: 9 pages, 5 figure