2018/05/31 by Fengcheng Wu, A. H. MacDonald, Ivar Martin · 1 citation
Physics and Astronomy · #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevlett.121.257001
published as Phys. Rev. Lett. 121, 257001 (2018) · 5+3 pages, 4+1 figures
arxiv created 2018/12/17 · arxiv updated 2018/12/19
We present a theory of phonon-mediated superconductivity in near magic angle twisted bilayer graphene. Using a microscopic model for phonon coupling to moiré band electrons, we find that phonons generate attractive interactions in both s and d wave pairing channels and that the attraction is strong enough to explain the experimental superconducting transition temperatures. Before including Coulomb repulsion, the s-wave channel is more favorable; however, on-site Coulomb repulsion can suppress s-wave pairing relative to d-wave. The pair amplitude varies spatially with the moiré period, and is identical in the two layers in the s-wave channel but phase shifted by π in the d-wave channel. We discuss experiments that can distinguish the two pairing states.