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تسجيل مستخدم جديدTheory of phonon-mediated superconductivity in twisted bilayer graphene
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We present a theory of phonon-mediated superconductivity in near magic angle twisted bilayer graphene. Using a microscopic model for phonon coupling to moire 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 moire period, and is identical in the two layers in the $s$-wave channel but phase shifted by $pi$ in the $d$-wave channel. We discuss experiments that can distinguish the two pairing states.
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